That Fish Blog – Aquarium Advice and Information

Hello, Frank Indiviglio here. Among the 150+ species of catfish classified in the genus Corydoras, all native to Central and South America, we find some of the most beloved of all aquarium fishes. Yet despite their willingness to breed in captivity, not many aquarists make the effort. As we will see, however, the droll cory cats employ one of the fish world’s most unusual breeding strategies…they are definitely worth a closer look!

Startling Reproductive Behavior

Female cory cats are larger than males, and their body has a thicker, more rounded appearance. In some species, the male’s dorsal fin is thinner and higher than the female’s and is held in a noticeably more erect position.

Corys may breed in either pair or group situations. Males chase gravid females, with the pair eventually lying motionless and perpendicular to one another (this is known to aquarists as the ‘T-Position”). The male lies on his side, and, amazingly, the female then uses her mouth to withdraw sperm from his vent.

Fertilization – Internal or External?

How fertilization actually occurs is still open to some discussion. Most ichthyologists believe that the sperm exits the female’s gills, and is shunted to a unique cup that she forms with her pelvic fins.

Upon obtaining the sperm, the female lays 1-5 eggs into this cup. She then moves off to a pre-cleaned site, usually a plant or the aquarium glass, where she glues each egg individually. She repeats this process with the same or another male until her clutch of 10-25 eggs is laid, an ordeal that may last 3-6 hours.

Some researchers have suggested that the sperm passes through the female’s digestive tract, to be released along with the eggs, or that the female expels the retained sperm upon the eggs. In any event, a most extraordinary means of fertilization…why such a strategy would evolve has not, to my knowledge, been explained.

Breeding Corydoras

While Corydoras cats may spawn spontaneously, the most consistent results will be obtained if cool, highly oxygenated water is added to the aquarium, simulating the drop in temperature and rise in water levels that accompanies the start of the rainy season in most Corydoras habitat. Dropping the aquarium’s water level beforehand may also help.

While various species differ in their requirements, the formula that I have used for bronze corys (C. aeneus) seems to work well in general. After dropping the water level for 2-3 weeks and maintaining it at 76 F, I add water of 60 F in an amount equal to 1/3 the volume of the tank.

Caring for Eggs and Fry

The eggs can be left in place and the adults removed (some are egg predators), or they can be carefully transferred to a rearing aquarium (they are fairly large and sticky for a day or so after deposition).

The fry should be housed in shallow water (3-4 inches) at first, as constantly rising to the surface for air will weaken them significantly.

Cory cats are, despite their “scavenger” reputation, highly specialized predators on tiny invertebrates. Their fry are best reared on live blackworms, brine shrimp and Daphnia, with animal-based flakes and pellets being added as they grow.

Plan to be in it for the long haul…a bronze cory in my collection is nearing 21 years of age!

Further Reading

Peru’s popular panda cory (Corydoras panda), described in 1969, favors cool, fast moving streams. To read more, please see

http://www.redorbit.com/education/reference_library/fish/panda_corydoras/2190/index.html.

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

Hi, everyone. Jose here. Ever wonder why some people keep certain species of fish over others? Some people like to keep Oscars and Jack Dempseys because they eat other fish, others keep African Cichlids for their colors. Some choose bloody parrots because they are “cute” (hahaha, sorry), yet others of you have angels and rams for their elegant fins and coloration.

My reason for being a “cichlidiot” (cichlid idiot) at first was their color. I started out Mbuna from Lake Malawi. I got a 55 gallon, a bunch of rocks and plants, and kept Pseudos and yellow labs. Well, the plants got trashed, so it ended up being a tank full of rocks. Then I added the Electric blue Ahli and a Bicolor Peacock (let the games begin). That poor peacock didn’t stand a chance between the Ahli and the Mbuna. Lessons learned along the way, my obsession with cichlids of all types and from all regions has contributed to a lot of fun and interesting aquarium adventures through the years. So, away with the pretty little Mbunas and onto Malawi haps, like the Eye-biter, the Livingstoni, etc. I went. Besides the outstanding colors, each species also had some very interesting feeding and breeding behavior that fueled my interest.

Next came the Victorians. These were smaller than the big guys I was used to, but with color and spunk, careful mixing of pairs (a lot of females look alike and you can end up with hybrids) my reason for these guys was the fact that they were almost wiped out due to the introduction of the Nile Perch to their native habitats. Keeping fish like these is a great way to keep species going.

Next for me were the Tanganyikans. The Brichardi complex with its long flowing fins got me hooked, then, I fell in love with Featherfins and Shell-dwellers. Tanganyika is a very diverse lake with multiple types of spawning rituals. You have egg layers, and mouth-brooders, and egg scattering species, all very interesting to breed and observe.

Then we have the West Africans. These colorful and interesting fish live in the rivers of West Africa, and include different types of Kribs, Jewel Cichlids, and not to forget, some of the tilapia species. After a few years, my madness moved on to South American Dwarf Cichlids and then the discus. Breeding them was an accomplishment.

Dwarf pikes and rams were next on my list, and the fun and headaches of keeping Central Americans soon followed.  They are bruisers; big, mean and with a lot of attitude, and even smaller centrals think they are their larger cousins with plenty of attitude for their size.

Finally I ventured into fish from Madagascar (most of which are either extinct or in danger of being extinct), which were a treat to keep. They are a lot like the centrals in behavior and habitat conditions. And I can’t forget to mention the Chromides from Asia and the new cichlid they’ve found in Iran.

Now that I’ve outlined the path of my decent into cichlid madness, I’ll talk about my favorites from each location in some future installments.

Until next time

Jose

Hello, Frank Indiviglio here. Please see Part I of this article for information on using plants and bacteria to control algae. Today I’d like to take a look at some algae-eating fishes, snails and shrimps.

Sucker Catfishes (Plecostomus, Hypostomus, Loricarichthys spp.)
An incredible array of fishes consume algae, with these interesting beauties being among the best known. Larger sucker cats and Chinese sailfin sharks (see article below) can also be kept in outdoor ponds.

Thailand Flying Fox, Epalzeorhynchus kallopterus
This nicely marked fish consumes all types of algae, and is also fond of the flatworms that sometimes arrive in aquariums along with live plants.

Siamese Algae Eater, Crossocheilus siamensis
This fish is similar in appearance to other, less-effective species, and is sometimes sold as the “True Siamese Algae Eater”. It does well in schools, and consumes even the coarser varieties of hair and beard algae.

Chinese Hillstream Loach, Beaufortia kweichowensis
This small loach is one of my favorites. It has been compared to a flounder in appearance, but reminds me of the oddly-shaped torpedo rays.

This active loach is adapted to fast-flowing waters, and fares best in high oxygen environments. It is well-suited for removing algae from glass and plant leaves, and is rarely if ever bred in captivity…definitely a fish worth working with for those interested in breaking new ground.

Garra pingi pingi or Pingi Log Sucker, Discognathus pingi
Formerly rare in the trade, this stout East Asian bottom dweller has a huge appetite for algae of all types. Many aquarists find they must supplement its diet with algae wafers; those I have kept took pre-soaked kale as well.

This is another species which would make a nice breeding project, as only wild-caught animals are available at this point.

Algae Eater, Gyrinocheilus aymonieri
The “standard” algae control fish in smaller aquariums, the taxonomy of this interesting species is somewhat of a mystery. While typically reaching 4 inches in length, I recall receiving shipments of individuals that topped 11 inches. I hope to keep some in an outdoor pond in the future, to see if the increased water volume might spur additional growth.

Algae eaters relentlessly comb rocks, glass and plant leaves for algae, and will take leftover fish flakes as well.

Freshwater Shrimp
Almost all of the dozen or so species currently available favor algae as food. Particularly attractive is the cherry shrimp, Neocaridina denticulata sinensis. Given proper care (please see article below) they will breed prolifically, with a large group making for a spectacular display.

Freshwater shrimp will co-exist with the fish mentioned above, but will, however, be harassed or eaten by fishes with carnivorous tendencies.

Snails
A number of snails live almost entirely upon algae, but many consume plants as well. Apple snails can eat a surprising number of plants overnight, while olive Nerites (please see article below) take only algae and do not reproduce in fresh water. The Japanese trapdoor snail is also a good choice, but needs warm, well-filtered water.

Further Reading
To learn more about some of the creatures mentioned above, please see the following articles:
Freshwater Shrimp

The Chinese Sailfin Shark

The Olive Nerite

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

Hello, Frank Indiviglio here.  Among the Cichlids (Family Cichlidae) we find some of the most interesting and highly desirable of all freshwater aquarium fishes.  Nearly all show a startling degree of responsiveness to their environment and owners, with many becoming true “pets” as opposed to animals to be observed only.  Included among the group are Oscars, Jack Dempseys, angelfishes, convicts and other popularly-bred species, as well as a number about which little is known.

Diversity and Range

With well over 1,300 species named to date, and many as yet un-described, this family is one of the fish world’s largest. Ranging in size from 1 to 36 inches, Cichlids inhabit the fresh and brackish waters of Central and South America, the West Indies, Africa, Madagascar, Syria, Israel, Iran, southern India and Sri Lanka.  One species, the Texas cichlid, occurs in the USA.  Found throughout the drainage of the lower Rio Grande River, it is the most northerly of all cichlids. 

A number have been widely introduced, with Oscars (velvet cichlids) being long-established in southern Florida.  I have collected them in the Everglades, and have reports of a great many other introduced populations.

Parental Care

One near universal trait among the family is the amazing degree of parental care given the young. In many cases both the parents tend to the fry, cleaning them and the nest site and driving off potential predators.  The lovely, popular discus (Symphysodon aequifasciata), a native of the Amazon Basin, feeds its young with a modified mucus secreted from the skin.

The Unique “Second Jaws”

Cichlids have a second pair of jaws in the throat.  Known as the pharyngeal jaws, these unique structures process food and have freed the primary jaws to develop an amazing array of adaptations to deal with specific and unusual food items.  Included in this family are species that feed upon bacteria, other fishes, hard-shelled mollusks, algae and an amazing assortment of other food items. 

It is speculated that specialized adaptations have allowed cichlids to become the dominant fish family in many of the ecosystems in which they occur.

African Rift Lake Cichlids

 In Lake Victoria and other water bodies of Africa’s Great Rift Valley live a variety of cichlids that have all evolved from a very small number of “parent species”.  About 90% of these fishes are endemic to a single lake, and the speciation process seems to have occurred in the relatively short time.  Up to 200 closely related species, often termed “species flocks”, may be found in a single lake. 

I’ll cover the care of individual Cichlid species in the future. Until then, please write in with your questions and comments.  Thanks, until next time, Frank Indiviglio.

Further Reading

We have posted a number of Cichlid care articles on our blog.  For information on keeping the popular and aptly-named Red Terror, please see The Red Terror: Cichlid Species Profile .

Ed. Note: Lots of cichlids are featured on our catalog photo contest located on Facebook.  Take a look here and vote for your favorite.

Patty here.

So, Summer is rapidly passing us by, and before we know it, Fall will be upon us.  I always dread the end of warm days for my plants.  After perfectly sunny and humid days provide them with perfect conditions to thrive, I have to shove the plants into every spare corner and windowsill of the house and pray that they will make it through another long, cool, dry winter.  This year I am especially dreading it, since this spring I invested in several ferns and trailing plants that are humidity loving, like Maiden’s Hair Ferns, and some others that are thriving in moist soil that I fear will not handle the transition to indoors for the long duration.

I think the solution to my problem might be one that I have been contemplating for a while now, the construction of a new Paludarium.  In my last entry, I wrote about Archerfish and the possibility/benefit of keeping them in a large Paludarium.  For anyone who is unfamiliar with the concept of this type of set-up, it is kind of a hybrid aquarium/terrarium with a land area and a water area capable of supporting a variety of plants and also a potentially terrific environment for fish and amphibians.  The set-up ends up looking like a slice of marshland or rainforest, and I think that some of my plants may be in for a winter holiday if I can pull it together for them. 

I actually have 2 spare aquariums to potentially use for this project, an old 55 gallon and a 65 gallon.  The 55 has been used before as a terrarium, but not as a true paludarium as the shallow aquatic side was completely divided from the terrestrial side with a length of plexiglass.  It served its purpose at the time, a green home for a couple of green tree frogs.  The water side was too shallow to keep any fish, but that will be remedied in the new 65 gallon project.

 Before I get started I’ll be doing some rearranging, so the project isn’t going to get off the ground for a while yet.  For now, I’m considering the components I’ll need.  Materials that I have on hand for the project are planting media (soil, flourite, clay pellets), submersible pumps/filters, heaters, lighting (though I may need to upgrade), plants (always on the lookout for more), and some other decor like stone fountains, wood and rock.  I’ll be acquiring or collecting some other materials I’ll need for construction gradually so that I can get set up by the time the weather turns cold.   I’ll need some PVC pipe and fittings some egg-crate, screen or landscape fabric, charcoal, sealant, and some other bits and pieces, maybe some plexi-glass and some cork bark depending on the layout I choose.  Design will be the next step, and the second part of the great paludarium blog.

I’d be interested to hear any ideas from readers who have attempted this before and have some insight. With such creative possibilities here, anything can be helpful.

Check out some interesting paludariums on YouTube.

Until next time,

Patty