That Fish Blog – Aquarium Advice and Information

Hello, Frank Indiviglio here.

Two articles addressing fresh water and marine fish conservation issues were published this week:

Oriental Weatherfishes in Spain

According to an article in Biological Invasions, the Oriental Weatherfish (native to eastern Russia, south and Southeast Asia) is now well established throughout Spain’s Ebro River delta, and has a foothold in the Onyar River as well. This is of particular concern because over 80% of the Iberian Peninsula’s freshwater fishes are already considered to be threatened, with introduced species outnumbering natives in most rivers.

Last year, studies of the eel fishery in the Ebro River revealed that 8.2 tons of non-target fish, representing 17 species, are captured along with each ton of eels (elvers) harvested.  Approximately 40% of these fish perish before they can be released.

Fishes of the Coral Triangle

Reef fishes are becoming increasingly popular on restaurant menus throughout Southeast Asia and mainland China.  Particularly hard hit are species native to the waters bordered by Malaysia, Indonesia, Papua New Guinea, the Philippines, East Timor and the Solomon Islands.  Known as the “Coral Triangle”, this region is home to 75% of all known species of coral.

According to a recent Conservation Biology article, spawning aggregations of local species have declined by 79% in recent years, largely due to over-fishing.  Groupers, 26 species of which are endangered, have suffered the most.  Conservation efforts are complicated by the large number of countries having interests in these waters.

Thanks, until next time, Frank Indiviglio.

For further information on the natural history and captive care of weatherfishes, please see:

http://blogs.thatpetplace.com/thatfishblog/2008/05/22/fish-for-the-cold-water-aquarium-%e2%80%93-the-oriental-weatherfish-misgurnus-anguillicaudatus-the-european-weatherfish-misgurnus-fossilis/

Hey Fish Bloggers!

Desiree here.

It’s the dead of winter….so invariably my thoughts go to planning my summer vacation.  Some fortunate colleagues of mine have already taken winter retreats to Florida or elsewhere.  But as I pour over maps and travel catalogs, and look at pictures from those friends in Florida, I have realized that you can’t take a fish nerd on vacation. 

It doesn’t matter where you go, the power of “fish nerd-dom” is impossible to overcome in any environment.  I think those of you who fall into this category know what I mean and are laughing hysterically right now.

If you are somehow not in this particular category of nerd – Imagine the last time you went somewhere, anywhere with a real “fish geek”.  In any city we nerds visit there’s ONE question… “Where’s the aquarium?”  We’ll go, not shut up once about anything we see, critique it according to where we’ve worked or visited in prior trips, and then move on to the next one.  Think camping is safe?  NOPE.  Wherever we are, we’re looking for a stream or pond where there are fun rocks to turn over or aquatic plants to identify and more likely than not – all sorts of mundane things (like riffles) to photograph.  OOOH LOOK – A cichlid in a ditch!!! 

And don’t even think of taking a beach trip!  Hobbyists are bad enough, but your trip is hopeless with a “Marine Biologist.”  We’ll instantly revert to stories of field studies, trawling trips, dive sites, and the obligatory drunken college boat trip.  We’ll wax philosophic for what seems like hours on the ramifications of eco-tourism, native fish collection, global warming and garbage vortices, much to the annoyance of those who aren’t quite so passionate about the subjects.

Non fish nerds can’t relate to any of this seemingly insane behavior and are instantly bored out of their minds and think “Here we go again!”  Well, like I’ve told my own non-nerd husband – you’ll have to grin and bear it.  Fish nerds are a passionate bunch and there’s just no way to take a “normal” vacation with any of us.  It’s best just to sit back and enjoy the ride, besides you might just learn something.

 I think New England looks good this year – so many rocky shorelines and tidal pools to fall into!!  Maybe I’ll turn over Plymouth Rock to see what’s under it.  It’ll be great!!

Until Next Time,

Desiree

Melisa here. Well, it is that time of the year again. It’s a bit chilly these days. What better to do than snuggle with the one you love or find someone to love…right?

The Anglers and frogfish that are commonly kept in our aquariums have much less complicated rituals.  Just before mating (usually 8-12 hours before), the females of many common types will begin to fill with eggs, typically 40,000 to 180,000!  Their abdomens become distended, making them quite buoyant.  When the male comes along he nudges the female’s abdomen, stimulating her to move to the surface where spawning occurs.  The eggs are usually released as an egg raft or veil that drifts along for a few days before dropping to the sea floor after the embryos hatch.  Post-planktonic frogfish (1-2 months old) take on the appearance of a perfect tiny Frogfish, but often display bright defensive colors!

Some species actually tend to the eggs, protecting the clutch until they hatch. Lophiocharon trisignatus males attach the egg clusters to their bodies until they hatch.  Some species hold the eggs not only to protect them, but also to lure prey closer with the eggs as a prospective meal for the clueless prey!

Deep sea anglerfish of the superfamily Ceratioidea probably have the most interesting way to find the” love of their life,” to say the least.

When scientists first started studying ceratioid anglerfish they were confused why all they appeared to capture were female anglerfish. It was also noted that most of these anglerfish that were studied had some type of parasite attached to them. It was later revealed that the “parasite” was actually what remained of the male anglerfish. With some further investigation scientists were able to tap into the secret lives of these anglerfish.

At birth the males are programmed to detect scents in the water. They immediately begin their search for a female in the deep dark depths of the ocean. As they mature, the males digestive system shuts down, making the males incapable of feeding themselves. If he does not find a female he will die. Assuming he finds a female he takes a big comp and attaches himself for life. The male anglerfish releases an enzyme that fuses his body with hers. From the moment they are one the male becomes an autotroph living off the female. As time goes by the male begins to degenerate, leaving only lump with is gonads enclosed to release sperm when the female releases her eggs. This extreme mating ritual assures that when the female is ready to release eggs they will be fertilized. 

If you know of any other bazaar mating rituals in the fishy world I would love to hear about them.

Until next time,

Patty

Back for another installment of FAQs submitted to Marinebio@thatpetplace.com!  Here are two questions we hear pretty often.  We’re here to help, so keep the questions coming.

Ryan wrote us with a common question about anemone behavior:

I have a pink-tip anemone in a seventy five gallon tank. I have had it for a couple months now and it seems to be doing good, but it never stays in one spot. It is always moving around on the glass, around the rock work, everywhere.  Is this normal? Is there anything I should do or just leave it alone?

Marine Bio responded:

That sounds like a fairly typical behaviour for that type anemone. They move constantly it search of favorable conditions as far as lighting, water flow, and feeding opportunity, as they depend a lot on food items passing by in the current that they can grab onto. It may eventually find an area that it favors and it may stay there for awhile, but probably not for extended periods.  Host anemones are often more prone to finding a position they like. In a spot with good conditions, they can anchor onto a solid surface for longer amounts of time, expanding to feed and take in the light, though they do move periodically as well.  Just make sure that any intakes to pumps or filters are covered with a sponge so that if he crawls on them he won’t get sucked into the equipment! Other than that you shouldn’t have to do anything except feed and maintain the aquarium as normal. They move to a happy place, maybe every day, maybe once a month.

 Beth wrote to MarineBio with a question about feeding:

I have a 75-gallon saltwater aquarium housing a lawnmower blenny, false-eye sharp-nosed puffer, long-nose hawkfish, spot-tailed wrasse, and 2 blue damsels. I feed my fish the frozen food and pellets recommended by the professionals at That Pet Place. I have been reading about the freeze-dried foods–shrimp, plankton, etc. I was wondering if freeze-dried food would be acceptable as an additional supplement to what I already feed them so that they are getting a healthy variety of foods to include all vitamins and minerals they need. If freeze-dried foods are appropriate, what would you suggest I get for my fish?

Marine Bio response:

Freeze-dried plankton and/or Mysis would work well for you. It is hard to give you fish too much variety. It is important to vary their diet as best as you can so that their dietary requirements are met and they don’t develop nutritional deficiencies, and that goes for any type of fish tank.  I typically recommend a good basic flake or pellet like Spectrum or Ocean Nutrition supplemented with a frozen mix and freeze dried treats appropriate for the fish you’re keeping. In your case, the fish you have will be most interested in a meatier diet, though some of them will happily take vegetable matter too, like sea veggies or bits of algae in the frozen formulas, especially if you lack natural algae growth. You can customize your feeding regimen according to their needs, but be sure not to overfeed the tank. Smaller amounts of a variety of foods can be fed at different times, or at your scheduled feeding time, but make sure the fish are consuming the foods and they are not falling to the floor of the tank or collecting elsewhere where they can cause water quality issues.  It sounds like you’re doing just fine!

Classification

More than 200 species of moray eels, all classified within the Family Muraenidae, have been described.  Like the familiar American eel, morays are considered to be true eels of the Order Anguilliformes.  The Superorder to which all eels belong, Elapomorpha, contains over 800 species, including the decidedly “un-eel like” tarpon.

Natural History

Although usually associated with tropical and subtropical habitats, a number occur in temperate seas, and several enter brackish and fresh water on occasion.  Ranging in size from the red-faced eel (Monopenchelys acuta), which reaches only 8 inches in length, to the 12.5 foot long giant green moray (Strophidon sathete), all share a similar body pattern and habits.  The latterly flattened body allows them access to the narrow caves and crevices that form their home base.  Many spend their entire lives within close proximity to a favored shelter, leaving only to mate and foraging nearby.

Some Interesting Facts

Morays can reach quite high densities in suitable habitats, accounting for nearly 50% of the carnivore biomass on some reefs off Hawaii.  Although nowhere considered a delicacy, moray eels are eaten on occasion, and instances of fatal poisoning (ciguatera) have been reported in the Philippines.  A number have unusual life histories…the leaf-nosed moray (Rhinomuraena quaesita) begins life as a dark blue-and-yellow colored male and later transforms into a black-and-yellow female.

Diet and Feeding

Moray eels are carnivorous, and in captivity will readily accept frozen silversides , sand eels , clams  and other fish, crustaceans and mollusks.  Local seafood markets are wonderful shopping grounds for the moray owner – be sure to try mussels, conch and various marine fishes.

Well-fed eels will coexist with smaller fish, but there is always the possibility of predation.  On the other hand, morays are not quick feeders, and indeed can be rather shy about this, so one must take care that they are getting enough food if they are housed with large, aggressive fishes.

Cautions

Moray eels are, like all their relatives, master escape artists.  If this occurs, be sure to move the animal back and forth in the aquarium once it is replaced, so that water is forced through the gills, and treat it with Stress Coat Marine to help replace the skin’s slime coat.

Even small morays are equipped with needle-sharp teeth, and they are not shy about using them in defense or if they mistake your finger for a tasty food item.  The resulting wound almost always becomes infected, and large animals can cause permanent damage.  These are definitely not fish for homes with children.

Longevity

Well cared for specimens can reach impressive ages in captivity.  A huge green moray I worked with at the Staten Island Zoo is still going strong at age 30+.

Snowflake Moray, Echidna nebulosa

Brilliantly patterned in black and white, this Indo-Pacific native averages 24 (rarely to 40) inches in length and makes an ideal first choice for one new to keeping moray eels.  Many individuals become quite tame, reaching out from their lairs to accept food offered on feeding tongs.

They are, like other members of their family, slow feeders, and so are best individually-fed if kept in a community aquarium.  Snowflakes readily accept all manner of frozen or fresh marine foods such as shrimp, clams and fish.  Like all morays, they will not thrive unless provided with a secure retreat.

Other Commonly-Available Moray Eels

The girdled moray (Echidna polyzona) hails from the Red Sea and Indo-Pacific and its small size (to 35 inches) suits it well as an aquarium subject.  It has a relatively small head ….food item size should be adjusted accordingly.

The attractively patterned reticulated or leopard moray (Gymnothorax tesselatus) also appears in the pet trade.  Pale reticulations on a dark background lend it a spectacular appearance, but it reaches 5 feet in length and is therefore suited only to large, very well-secured tanks.

Please write in with your comments and questions.  Thanks, until next time, Frank Indiviglio.

You can learn more about moray eels at:

http://www.fishbase.com/Summary/FamilySummary.cfm?ID=56&CFID=17425107&CFTOKEN=61585937