That Fish Blog – Aquarium Advice and Information

Please welcome back Frank Indiviglio with another article.

Those of you who use blackworms as fish or amphibian food have likely been surprised (or horrified!) to find small leeches in among the worms. My own curiosity and questions from others led me to take a closer look. Upon doing so, I was amazed to see the leeches sucking down the blackworms like spaghetti!

Leeches are, of course, best know for their blood-sucking ways – but it turns out that a great many of the over 650 species are actually predatory (although the largest, the giant Amazon leech, Haementaria ghilianii, does suck blood – and, at 12 inches in length, quite a lot of it!). Blood sucking forms, it seems, evolved from predatory leeches.

I established a colony of the leeches in an aquarium and found them to be exceptional scavengers (as are blackworms themselves). They emerged from the gravel bed at night (they are sensitive to light – I was able to best see them by using a night viewing bulb) and made short work of dead fishes and leftover food, and were very effective at reaching areas below rocks and the filter. They showed no interest at all in the loaches, African clawed frogs, snails or shrimp that shared their aquarium (at least while the foregoing were alive!). The leeches deposited their eggs in a case attached to the undersides of rocks. The egg case’s covering is tough and leathery, and obviously offers good protection against predators.

I believe it would be worthwhile to investigate the use of this leech as an aquarium scavenger. I am still uncertain as to the species, and had one unexplained die-off, and so would greatly appreciate hearing from anyone who might have further information. Thanks. Until next time, Frank.

General information on leeches is available at:
http://www.austmus.gov.au/factSheets/leeches.htm

Thanks Frank!

Dave

Today I’d like to introduce you to the maintenance of cold water aquariums, a fascinating but often overlooked branch of aquarium keeping focusing on marine and freshwater fishes and invertebrates from temperate regions.

Exotics Close to Home
Please don’t be misled into equating exotic and interesting creatures with “far-off, tropical places”. Shorelines, ponds, tidal pools and rivers throughout the world’s temperate regions (with the exception of extreme s. Florida, the entire USA is in the temperate zone) yield animals of unimaginable variety and interest. While it is true that many of the most spectacularly colored fishes are found in the warmer parts of the world (their bright colors likely help males and females of the same species recognize each other among the great diversity of similar species in the tropics), breeding males of many temperate fish species, i.e. the sunfishes, do rival those of their tropical counterparts.

Why keep Temperate Fishes and Invertebrates?
Animals from temperate areas offer many advantages to aquarists who live in the USA. Often, our normal seasonal rhythms of temperature and light fluctuation are sufficient to encourage such creatures to exhibit natural behaviors, and even to breed. Also, it is often easier for us to provide a wider range of foods and a more natural environment for them than we can for creatures from faraway places. In some cases, where legal, we may even be able to collect and keep native fishes and invertebrates.

Creating Natural Habitats
If you live near a body of water, try to observe firsthand the environments and habits of a variety of aquatic creatures. You might consider modeling your aquarium after a particular habitat — a tide pool, a weedy, fresh-water pond, or a river bed, for example. Take note of the local substrates, rocks and other natural items and purchase similar ones when setting up your tank prod (collecting natural substrates is risky, due to the possibility of mineral, pesticide or other chemical leaching).

Heat
Cold water aquariums are maintained in a similar fashion to tropical aquariums, but we must consider the effects of heat. Many animals from temperate regions are very sensitive to rising water temperatures and to the lower oxygen levels that accompany them. You may, therefore, need to install a chiller to moderate temperatures during the summertime.

Species to Consider
Some of the animals that I have maintained with success in cold water aquariums, and which I plan to cover in future additions to this article, include American eels, fifteen-spined sticklebacks, pygmy and other sunfishes, mantis shrimp, sea stars, Chinese sailfin suckers, weather fish, horseshoe crabs, blue claw crabs, bullheads and madtoms, white clouds, various snails, crayfish and shrimp, giant water bugs and other aquatic insects and many others.

I’ll now give a quick overview of two unusual animals – the oyster toadfish and the spider crab – which are easily maintained in unheated marine aquariums. I’ll cover their husbandry in detail in future articles.

Oyster Toadfish, Opansus tau
This unusual marine fish, ranging down the Eastern Seaboard from Maine to Cuba, seems to cross the line between fish and amphibian – its face even resembles that of a toad. In addition, toadfishes produce sounds audible above the water and certain Asian species can travel overland for considerable distances.

Oyster toadfishes will become quite tame in captivity, and, given a tank of 55 gallons or so, may well breed. Males are ferocious guardians of their eggs, and have been known to stay with nests that are exposed at low tide.

Oyster toadfishes have survived for 15 years in captivity, and will accept nearly any meat-based frozen or pelleted food as well as live shrimp, small fishes and worms. They learn to associate their owners with food, but will bite when handled, and the spines that can inflict painful wounds.

Atlantic Spider Crab, Libinia emarginata
Spider crabs, common yet fascinating if you take the time to know them, are members of a family which includes the Japanese spider crab. With legs spanning 8 feet, these giants awed me when first I observed a large group in a pubic aquarium in Osaka, Japan. American aquariums now exhibit them as well – trust me, they are well worth the trip.

The Atlantic spider crab is a valuable aquarium scavenger, and, using its tiny pointed claws to probe into nooks and crannies, misses little. Younger animals have the endearing habit of jamming algae and vegetation into the crevices of their shells, taking on the appearance of a “walking plant”. They will also nibble at this portable garden from time to time. I have found that they forgo this habit when they reach a carapace size of about 3 inches, although I have yet to discover why.

Spider crabs rarely bother tank-mates and readily consume fish flakes, pellets, blackworms, frozen food fish foods, algae and green leafy vegetables.

In the next installment of this article I’ll write about temperate, fresh water animals that are readily available in the pet trade. Until then, please write in with your questions and comments. Thanks. Until next time, Frank.

Information on the natural history of the oyster toadfish, along with a photo, is available at:
http://fishbase.mnhn.fr/Summary/SpeciesSummary.php?id=3069&lang=Portuguese

It is the time of year when carnivals and fairs pop up across the land, with games and rides and fun for all (well the kids anyway). What that brings to mind here at TFP are all the unsuspecting parents who have suddenly become the proud new owners of a pet fish that their kids have won as prizes in these games, and need to know how to take care of them. Every year we sell thousands of fish to carnivals as game prizes, and then find many people who need help with their new “prizes” after they get them home.  We’d like to take some time to review the most common fish found at your local carnival or fair.

Goldfish

The practice of keeping goldfish (Carassius auratus) dates back to as early as 970A.D. when domesticated fish keeping began in ancient China. Farmers would impound carp as food fish, these carp where silver grey fish, like the wild carp found today. A genetic mutation in some of the carp gave them a yellowish gold color. The farmers would then selectively breed these colored carp, over time this selective breeding lead to what we now know as the modern goldfish. As the popularity of these fish grew, and they spread out from China, selective breeding of various mutations in the species has given rise to many different types of goldfish over the centuries. These different types of goldfish include the Oranda, Ryukin, Shubunkin, Comet, Lion head, Bubble eye and more. Goldfish are seen as good luck symbols in many oriental cultures and some breeds even have religious roots; the Celestial Eye goldfish were bred because monks believed their eyes looked towards the heavens.

Temperament

Goldfish are peaceful fish that do well with other breeds of goldfish or other cold water fish. There are little to no issues with aggression, aside from the odd individual or “nippier” variety. It is not recommended to mix goldfish with tropical fish (tetras, guppies, etc) due to differences in water quality and temperature preferences. Goldfish prefer aquarium water temperatures from 60 – 74 degrees. Goldfish are commonly kept in outdoor ponds that will reach freezing temperatures in winter, provided it can not freeze solid, and a floating heater is used to insure constant gas exchange. Goldfish will tolerate a wide range of pH values, from 6.0 to 8.0, so long as conditions are stable.

Size

Most types of goldfish will reach a maximum length of 6”- 8”, Comet and Shubunkin Goldfish can reach 12” or more. Goldfish can live up to 20 years given a proper diet and water conditions; there have been recorded accounts of goldfish living into their 40’s

Feeding

Goldfish are easy to feed as the will accept virtually any types of fish food. Flakes or pellet formulas especially for goldfish are best. Avoid meaty foods, goldfish have a high vegetable requirement. Vegetable matter like algae sheets, cucumbers, or peas can be supplemented into the goldfish’s diet to help maintain optimal health.

Care

Goldfish tend to be messy fish, with a big appetite, which leads to large amounts of waste. As a result monitoring goldfish’s water conditions is very important. It is not recommended to keep goldfish in unfiltered bowls, although it is possible if frequent (usually bi-weekly) water changes are consistently done and the water remains aerated. Live plants can be used, although they will usually end up eaten as the fish get bigger. The best environment for goldfish is an under stocked aquarium with ample filtration and regular maintenance.

Bettas

The Betta fish, Betta splendens, is another commonly found “prize fish” that you may have the pleasure of become the new owners of. Bettas are one of the most beautiful freshwater fishes that are available in the aquarium hobby; their striking color and ornate finnage are quite remarkable.

History

Bettas are often chosen as prizes because of their ease of care, and ability to do well in very small amounts of water. The Betta is native to areas of Thailand, where they are exposed to times extreme rainfall and drought, which during times of drought can result in little more than a puddle to live in. Unlike most fish, the Betta does not solely rely on oxygen from the water it resides in, it has the ability to breathe air. Bettas are members of a group of fishes called Labyrinth fishes. Labyrinth fishes have a specialized breathing organ, called the labyrinth, which allows them to breathe air at the waters surface, somewhat like a primitive lung. The ability to breathe air allows the Betta to survive in very warm water with little or no dissolved oxygen. This is how Bettas are able to cope with very small fish bowls, and is often how they are displayed and sold.

Habitat

PLEASE do not use this as an excuse to keep a Betta in extremely small environments for extended periods: although they can survive in only a few ounces of water, they will not be happy and comfortable.

Bettas can be kept in unfiltered bowls, provided adequate water changes are maintained (at least 20% per week), and water quality is monitored. Larger aquariums of at least several gallons are preferred, the bigger the better. There are a number of small desktop aquariums that are ideal for Betta keeping.
There is another side of the Betta fishes heritage that there is much controversy surrounding. Another common name for the Betta, is the fighting fish, or Siamese fighting fish. This name comes from the aggressive nature that these fish have towards one another, especially two males. The Thai name for these fish is”pla-kat”, which means biting and tearing fish. When placed in the same tank, two male Betta fish will literally fight to the death. There is a whole world of fighting and gambling involving the Betta in other cultures. Fighting Bettas is not considered an appropriate practice in the hobby.

Feeding & Care

There are many commercially produced Betta foods, in pellet, flake and freeze dried forms. A good varied diet is best. Feed only as much as the fish will eat in a few minutes, take extra care not to overfeed, especially in unfiltered bowls. Bettas prefer warm water, 72-78 degrees, so avoid cool areas like window sills, and hallways when possible. Direct sunlight should also be avoided; this will lead to unwanted algae growth, and temperature fluctuations during the day. While you can not keep bettas together, they can be kept in peaceful community tanks, with other types of fish.

If you have any futher questions about goldfish, bettas or other carnival fish, post them and I’ll be sure to answer. I hope that this has helped all you new fish owners out there, or even peaked the interest of anyone that is considering a fish.

Until next time,

Dave

Octopuses have much going for and against them as pets. They are, without a doubt, the most intelligent of the invertebrates, and often seem to rival much more “advanced” creatures in brain power. Able to distinguish and associate various shapes with a food reward, some have even learned to unscrew glass jars to obtain food. In one laboratory, cameras revealed that an octopus was leaving its aquarium each night to prey upon crabs held in a neighboring tank. Each morning, the octopus was found back in his own aquarium, having crossed several feet of dry shelf space in his nocturnal travels! One that I kept would, according to my grandmother, “watch her” as she prepared dinner (octopus see very well, and notice movement outside their aquariums). Unnerved by the thought of our pet witnessing the demise of his relatives, she would cover the aquarium with a towel on those days when she cooked octopus or squid for dinner!

On the down side, however, all species studied are quite short-lived (2 years at most) – quite odd considering their complex lifestyles. Males generally expire right after mating, and females survive only long enough to see their eggs through hatching.

The species most often seen in the pet trade is the common tropical octopus, Octopus cyaneus (please note that there is a good deal of confusion as to the identification of this species). Growing to a maximum length of 12 inches, it does well if provided excellent water quality (manage it as you would a delicate reef fish) and a secure retreat in which to hide. Octopuses absolutely need to hide and are intolerant of disturbance (although once acclimated many will become quite bold at feeding time). It is also important to avoid suddenly putting on a light if the room in which the aquarium sits is dark. When disturbed, octopuses release a dark-colored ink (sepia), which can be toxic to the animal in close quarters.

Bear in mind that octopuses consume large amounts of food and produce copious waste products – good filtration, frequent water quality tests and water changes are vital if you are to keep them successfully. Give your octopus the largest aquarium possible (this will help with water quality and in reducing stress on the animal) and be sure the lid is weighed down or otherwise fastened. The common tropical octopus does well at temperatures of 76-78 F. As most species are nocturnal, you should equip the aquarium with a bulb designed for nighttime viewing so as to be able to observe your pet without disturbing it.

Most octopus favor crabs, shrimp, clams, scallops, mussels and other shellfish, but usually take fish as well. Seafood markets are useful sources of food for your pet – as we know little of their nutritional requirements, I suggest providing as much dietary variety as possible. The wide range of frozen marine foods now available will provide you with a great many options as well.

Other species sometimes offered for sale include the red or pygmy octopus, O. bocki, which is highly nocturnal, and the common octopus, O. vulgaris. As the common octopus occupies a range spanning the Mediterranean, the Sea of Japan and the Eastern Atlantic, it is likely a fairly hardy creature. However, with a leg-span approaching 3 feet, it is too large for most home aquariums.

It is important to remember that all octopuses, even very small ones, can inflict painful bites with their sharp, parrot-like beaks, and that they can never be considered “tame” enough to handle. Most if not all produce venom in order to subdue their prey, and even venoms not shown to be dangerous to people can cause severe or even fatal reactions in particularly sensitive individuals. Amazingly, the tiny the blue-ringed octopus, Hapalochlaena maculosa, quite capable of killing a human with one bite, is sometimes offered for sale. Learn to recognize this species and avoid it at all costs.

Breeding octopuses in captivity is difficult, as is raising the young. Recent research at the Spanish Institute of Oceanography indicated that dietary factors, especially the absence of fatty acids such as DHA and EPA, are responsible for high mortalities among those that do hatch in aquariums. Enriched brine shrimp have been used with some success, but more variety is likely needed. I would experiment with various species of marine shrimp, worms, plankton and tiny marine creatures seined from eel grass beds and other marine habitats (check the legality of collecting before doing so).

Octopus husbandry is in need of much attention by serious hobbyists. These fascinating, complex creatures are impacted by habitat loss and collection for the food, bait and pet trade. Breeding them in captivity will certainly take pressure off wild populations and help in understanding what they need to survive in the wild.

Please write in with your own thoughts and questions. Thanks…until next time, Frank.

You can see photos of hatchling octopuses and read about a captive breeding effort at:http://www.bbc.co.uk/norfolk/your/a-z_norfolk/a-z_octopus.shtml

Please welcome back Frank Indiviglio with another interesting article.

Studying fish behavior is both a fascinating and very practical endeavor for the fish keeper. In addition to opening one’s eyes to the amazing diversity of fish lifestyles and behavioral adaptations, research concerning your pets’ natural behaviors will also lead to much greater success in keeping and breeding them.

The primary motivation behind animal behavior is survival – breeding, finding a suitable environment, obtaining food and avoiding predators (yes, human behavior often seems to break this rule!). Of course, even the best-designed aquarium is a poor mimic of nature, and so captive fishes must modify their behaviors – sometimes so much so that the actual purpose or function of what the fishes are doing will be lost on us. However, with experience, you should be able to see the relationship that the captive behavior has to its natural counterpart.

A wonderful aspect of the study of fish behavior is that it will provide a lifetime of surprises – there is far too much for any one person to know, and new facts emerge, quite literally, on a daily basis. With careful observation and research, you may well be able to discover something new. Today I will focus on just one facet of behavior – the time at which fishes are active, and how this affects their welfare in the aquarium.

When selecting fishes for your aquarium, it is important to consider whether they are diurnal (active by day), nocturnal (active by night) or crepuscular (active in the dim light of evening and early morning). This will affect both your enjoyment of your pets and the composition of species that you might wish to include in the aquarium.

Nocturnal fishes such as the fire eel, Mastacembelus eyrthrotaenia, and other freshwater eels, need a place to hide during the daytime. If denied this, they may become stressed and will languish in captivity. However, eels, catfishes and other species that barely move by day change radically at night, and may engage in a surprising degree of activity. These nighttime wanderings may disturb diurnal fishes and prevent them from resting properly, thereby impairing their health.

Unlike the always “ready-to eat” oscar, Astronotus ocellatus, and other Cichlids, nocturnal fishes often appear placid by day and morph into quite aggressive predators only as night falls. For example, octopuses, snowflake moray eels, Echidna nebulous, and similar species are usually quite content to spend the day secluded in a favorite retreat – easily tricking the novice into believing that they are compatible with their tank-mates. At nighttime, however, they undergo quite a change, and will quickly devour smaller neighbors.

Many diurnal fishes, such as the princess parrot fish, Scarus taeniopterus, and related species, swim about actively in daylight but secrete themselves within caves at night. Again, if you see them only during the day, you may miss such points and fail to provide for their needs (shelter-sleeping species become stressed if forced to remain in the open at night).

Please bear in mind also that many nocturnal fishes will not feed during the day. Some, including most catfishes and moray eels, will forego their nocturnal habits once they adjust to captivity. Many, however, (i.e. the fossil catfish, Heteropneustes fossilis) remain strictly nocturnal even after years in captivity, and must be fed at night if they are to thrive.

Just as nocturnal species may unsettle diurnal fishes at night, actively swimming fish (by day or night) may stress species that are largely sessile (fish which move about only occasionally). Most typical “sit and wait predators,” such as the various anglerfishes, will be greatly disturbed if forced to remain in close proximity to vigorous, mobile species (also, bottom-feeding predators usually do not obtain enough food when kept with surface-feeding fishes).

The best way to observe nocturnal fishes, and to see how diurnal fishes behave at night, is by utilizing a bulb designed specifically for nighttime aquarium viewing. Be sure to invest in such bulbs, as they will open up an entirely new world of fascinating observations and learning opportunities for you. If you plan to focus on nocturnal fishes, you may wish to consider a complete reverse light cycle, in the manner of zoo exhibits for nocturnal creatures. If a dimly lit room is available, you can leave the night-viewing bulbs on during the day, and give the fishes their “daytime” at night. This may give you more time to observe your nocturnal fishes – unless, of course, you are yourself “nocturnal”! I have been able to learn a great deal about a number of animals, both at home and while working at zoos, in this manner. Be sure to research your fishes’ natural history so that you can provide a day/night cycle of the proper length.

I’ll explore other aspects of fish behavior in future articles – until then, please write in with your observations and questions. Thanks, Frank.

An interesting article concerning the effect of light on fish activity is posted at:http://www2.hawaii.edu/~delbeek/delb12.html

Thanks Frank,

Until Next Time,

Dave