The following is a brief overview of some of the commonly encountered fish available in our local fish stores that grow to sizes difficult for the average aquarist to cope with in conventional aquaria. Hopefully this article will teach people what fish to avoid and they will further spread the knowledge on to others. Should you have a large enough tank and youâ€™re able to meet the needs of any of these fish then by all means go ahead and try them out. Though many of them are very inappropriate some of them are commonly kept by those with the proper setups. Lima shovelnose, kissing gouramis, bichirs, plecos, the few brackish fish in this articleâ€¦they all are good choices.
It is important to note that fish don't grow to the size of their tanks; they grow with the quality of the water. Many people will say they grow only as big as the tank allows and thus larger fish are alright in the smaller home aquarium. Not true, healthy fish will keep growing; in fact most fish never stop growing at all during their lifespan. It is water quality and improper care that stunts fish and as a result a stunted fish is an unhealthy fish. Done right, most fish have a similar growth potential in captivity as they do in the wild, this is why it's so important to pay attention to the size your fishes reach and to make sure you can accommodate them as adults.
This list is far from a complete write up. There are many other fish that could be placed on this list, and perhaps someday I will do another. Let this brief list serve as a warning that just because a fish can be found at the LFS does not mean it should be taken home or even sold for that matter. Readers are encouraged to do as much research as possible BEFORE they purchase any species no matter the size they reach or requirements they need.
These fish are members of the Cobitidae family within the cypriniform order. There are 160 or so species, all of them native to Europe, Asia and Morocco. This is an interesting and unique family of fishes and many make great alternatives to catfishes.
Clown Loach(Chromobotia macracanthus) Without a doubt one of the largest and most popular loaches in the hobby. These fish are great aquarium fish if properly cared for but sadly often end up in poor situations. Though they are considered a slow growing species they do grow quite large, up to or over a foot in length. They also can live for 50 years and thus require a long term commitment. Other possible turn offs about these fish are their social nature, you MUST have more than one for them to be happy, preferable a group of at least three. This will require a much larger tank then a single fish would need. They are also sensitive to water conditions, due in part to their lack of scales. They have sharp spines close to the eye that make them difficult to handle and when first purchased are typically in bad condition, it's easy to loose a clown loach fresh from the LFS. On the plus side, they are very fun and comical to watch. Their markings are unique within the loach family. Though it takes a long time to reach it their adult size is very impressive.
Dojo or Weather Loach (Misgurnus anguillicaudatus) Another common, attractive loach commonly sold in LFS. Like the clown, they grow large. Between 8-12”. Unlike the clown however they are not a tropical species and are sadly, often mistakenly thought of as such. There temperature should ideally not reach above 77 degrees. Good alternatives would be other eel shaped loaches like the kuhli loach who only reaches 4” and is a tropical species.
This is a group of primitive fishes within the order Polyopteridae. There are 18 species and they all grow large. They are an odd group with fleshy, stiff pelvic and pectoral fin, rudimentary lungs and a tetrapod-like jaw structure. All of them can be found in Africa. The species most commonly found in LFS is probably the senegal bichir and the ropefish. The Senegal can reach a foot to 20” in length and the ropefish can reach about 35” in length. Many bichirs are commonly kept and easy to keep, others are not. With 18 species it's important to note that research is in order, make sure you have a proper ID on whatever species you are buying. Should you purchase a ropefish make sure you have a very tight fitting lid with as little openings as possible, these fish are known to escape from their tanks often.
Like the knifefishes this is a generic name given to a number of fish that aren't actually eels and are often not even related. The eels in this article belong to two different families.
Mastacembelus Eels This is the family that most eels common in the hobby belong to. Many of them are staples in LFS. Among them are the fire eel (Mastacembelus erythrotaenia) who reaches 39”, tire track eel (M. armatus) who reached 29”, spiney eel (M. circumcinctus) who reaches 6” and the peacock eel (M. aculeatus) who reaches 15”. Obviously the only one on that list really suited for most keepers is the spiney eel but even then all of these eels require unique setups and diets. They prefer a sand type sub straight that they can bury themselves in. Where diet is concerned they often prefer frozen foods like blood worms and shrimp and won't take others. Their uniqueness also means that when placed with other fish special care must be given to make sure they get their share of food. All of these eels are native to Asia, there are 67 species total.
These fish belong to the family Muraenidae. As far as moray eels are concerned it is probably the best for the aquaria lifestyle but even still it is capable of reaching between 2-3 feet long. The biggest problem with these fish is that they are not freshwater despite fish shops across the country keeping them in freshwater and selling them as freshwater fish. Though they can tolerate low salinity and freshwater for a short time they will eventually die in it.
A family of fishes closely related to cyprinids, the family is scientifically known as Catostomidae. Most members of this family are not common in the hobby at all. There are 80 species found in North America, China and Siberia. All members of the family have a sucker-like mouth used to feed of the bottom and sling to structures in fast flowing waters.
Most fish shops get these fish in from time-to-time and sell them for a pretty high price. Highly attractive when young these fish change dramatically as they age, they eventually loose their attractive markings and high dorsal fin. They are capable of reaching three feet in length but seldom reach that size in captivity, partly because they grow very slow (about an inch a year) and often donâ€™t live very long in captivity. They are nitrate sensitive and prefer cool fast moving water. Most importantly these fish aren't very common in the wild and seldom captive bred, they really donâ€™t belong in the hobby.
The Belonidae family is comprised of 34 species, most living in marine environments. Their slender shape and long toothy mouth is very much like that of the gar family (Lepisosteidae) with whom they are not related.
Also known as freshwater garfish these are the only member of the Belonidae family you're likely to encounter in your LFS. Though they are capable of living in both brackish and marine conditions most live out their lives in freshwater. They are native to southeast Asia and can reach 12” in length. In addition to their size they are very nervous, skittish fish often darting around the tank and injuring their delicate jaw. They are also difficult to feed, often only taking live foods.
A note on photographs: Originally I set out to locate photos for each fish but was unable to get permission from their owners. The photographs that I was able to get were kindly provided by Jean-Francois Helias, owner of Fishing Adventures Thailand. (http://www.anglingthailand.com) The photograph of the weather loach was provided by myself. sandtiger