As far as catfishes go, pimelodids are far more "eat 'em uppers" than cleaner uppers, with even small species possessing and utilizing relatively large mouths to suck up their tankmates, particularly at night. And some of this families members are amongst the largest of freshwater fishes, reaching several feet in length, and quickly so under propitious aquarium conditions. There are only a few "rules" to abide by in the keeping of pimelodids; selection of initially healthy stock, some basic water quality provision, avoidance of toxic, but common medications. Here we'll detail the more common species available, their simple husbandry and some pointers on what to avoid in their aquarium care.
About the Family Pimelodidae ("Pim" "a" "low" "di" "dee", Greek, pimele = fat + Greek, eidos = similar):
For those who thought they knew about all because they've seen a striped and pictus catfish, a really big red-tailed cat, a shovel nose and crosses of the same, you're in for a bit of a shock. This Central and South American and some of the larger Caribbean islands catfish family is composed of some 56 genera and 300 and counting species. Pimelodids are characterized as possessing a pair of long maxillary/upper barbels/whiskers and two pair of shorter mandibular ones, naked (scaleless) bodies, possess elongated adipose fins, and importantly possessing or not stout spines on the anterior of their dorsal and pectoral fins (more about the latter below).
Size-wise: Whereas some of the smaller pimelodids max out at a few inches in length (genus Microglanis), the not-uncommonly offered Red Tailed Cat, Phractocephalus hemilopterus can grow to more than 4 foot in length, and Zungaro zungaro at five are dwarfed by the giant of the family, Brachyplatystoma filamentosum at about 3 meters.
Selection: Know Your Species! Planning ahead: Tank size, shape and tankmates.
These catfishes are demersal, spending almost all their time on the bottom, at times being quite active during the day, but principally hunting for food by dark of night. They prefer larger quarters that are aquascaped in such ways that allow them to turn around easily and get out of bright lighting. We mention this here to forewarn folks who might want to acquire pimelodids that they will do well only in this sort of setting.
Healthy Pimelodid cats are clear skinned and bright-eyed. They breath in a regular, non-labored fashion. Though newly-arrived specimens may well have burned, bitten or rubbed down "whiskers" (these barbels will re-grow if not too reduced), new purchases should be housed by themselves or conspecifics that are apparently disease and marking-free. Pay especial attention to parts of the body near fin origination for bloody spotting. Avoid all specimens in such systems.
Time on hand can be a useful indication of health. If you're considering an expensive specimen, you are advised to place a substantial deposit on it if it's newly arrived and hold off a good week or more before picking it up. Many mysterious losses occur within a few days of these fishes arrival (all are wild-caught) and a few days of resting up will generally show whether the specimen is going to recover from the rigors of collection and transport or not.
Species Commonly Offered To Aquarists:
Water conditions listed are from fishbase.org and are details recorded in the species natural range.
Tank size: We've touched on the need to be aware of the size and shape of systems these fishes need; that is, large and wide. Do provide a setting that is at least three times these animals maximum length (see Fishbase.org re) and once in width sans aquascaping.
Water Quality: Especially on first arrival these fishes appreciate warm (low eighties F. on up), softer (DH under 10), acidic water (pH 5.5-6.8). Yes, some species do hail from harder, more alkaline water quality and cooler climes, but the vast majority do not. Meet them at least half-way if your water is naturally more hard and alkaline than the above by preparing their acclimation water and system with filtered or supplemented water.
Bright lights, big city: This family is largely nocturnal with some of them hunting by day, but in generally turbid waters. They don't appreciate too intense lighting and if you do want yours to be happy but want your system well lit, you'd do best to provide a darker cave, over-hang, even section of plastic pipe or clay tile for their day time enjoyment. Along with providing shade we should mention providing some outside light to prevent spooking these fishes. Sudden bright lighting or commotion outside their system for that matter, can result in large specimens thrashing about, possibly seriously injuring themselves and your system.
Filtration, aeration, circulation: Being big, messy eaters and occupying all-too-often too-small quarters can be problematical in terms of waste accumulation and its concomitant ills. These fishes need well-aerated, clean water. Lots of circulation, frequent water changes, periodic use of chemical filtrants like activated carbon, along with appropriate feeding and under-crowded settings will keep yours healthy. Do supply on redundant sources of aeration and circulation such as powerheads and airstones, and be on constant vigilance for deteriorating water quality. Your catfish will suffer for it otherwise. Due to digging, dispense with using undergravel filters with large pimelodids. Filters should be large and external.
Large Pimelodid tanks need to be tightly and securely covered. These are very powerful fishes that can and do push off and "jump" out of their tanks rather often. Also, make sure that there are no sharp edges that your cat may cut itself on during occasional forays to the surface. These fishes are facultative aerial respirators and go to the surface occasionally for a gulp of air. On a related note, all breakable (e.g. heaters, pump intakes/discharges...) and swallowable (e.g. air-stones...) need to be protected from big cats marauding ways. These are best hid behind large, immobile aquascape elements or remoted to sumps outside the cats reach.
Decor should be kept to a minimum, to allow space
for your cat/s to move, outside of provision of aforementioned
habitat/shade. Avoid sharp rock to prevent physical injury and use
rounded, larger grade gravel or round stones to ease maintenance, waste
removal and disallow cloudiness from these animals digging.
Other species should be definitely larger than mouth-size and if possible introduced ahead of these predatory catfishes. Who knows how many small tetras, barbs, danios et al. have been inhaled by dark of night by pimelodids? This is a very large number. Other slower bottom feeders are best left out of systems that house these catfishes, as there is strong likelihood that they will not get sufficient food... and may well end up inside (and puncturing the stomach of) your Pimelodid/s.
Territoriality can be an important factor with these fishes. The larger species are best kept one to a system, perhaps as the only occupant, or if you're interested in breeding them and hence raising them in a group, in very large quarters (hundreds to thousands of gallons), with at least one good, well-placed hiding spot per individual. Even then, they should be carefully observed for agonistic behavior and to assure all are feeding. For species that grow large and are rapidly getting there, tankmates need to be fast, smart and possibly expendable!
Other than common disease and outright poisoning by well-meaning aquarists trying to treat same, most pimelodids are lost through consequences of a lack and mis-feeding. In the wild most pimelodids are nocturnal feeders, though they can/will adapt to daytime meals in captivity. Most are not very active during the day (w/the exception of the smaller Pimelodus species!), but even less motile with too frequent or over-feeding. For new arrivals, offering meaty, mouth-size morsels just past "lights-out" is recommended, and for all but the smallest individuals, once daily feedings should suffice. A word of caution re feeding whole fish to your larger Pimelodid cats: take care to remove the spinous fin rays of such whole foods, or better still, dispense with using them altogether and fillet them instead. And the usual admonition re feeding "feeder" goldfish. Other than being expensive, inconvenient and encouraging bad behavior, "feeders" are a veritable fount of parasitic disease. Avoid their use. Cut fish, beef heart, crabs/prawns/crayfish, worms of all sorts including insect larvae called such, are fine for larger catfishes. Smaller species, specimens gladly take prepared, frozen, pelleted foods of all sorts.
Newly arrived specimens are almost always starved if not near-starved as a consequence of food deprivation in anticipation of shipping. These animals should be catered to immediately and watched for signs of feeding, hollow-bellies... and offered food choices toward night time.
Feeding strikes amongst these fish species is not uncommon and should not be a cause for alarm unless they persist for weeks and the specimen/s appear to be wasting. Oftentimes, a change to a new food type (live earthworms, shrimp, cut fish...) will reverse a cessation in feeding.
Diseases: Trouble: Metal and Dye Medications & Not Pimelodids:
If received in initially good health, properly acclimated and kept in suitable conditions, Pimelodid catfishes are remarkably tough... Given other pre-disposing influences they are veritable disease magnets, particularly in regards to Ichthyophthiriasis, white-spot disease. Cures for this and other maladies are the usual checking for what may be amiss in the way of water quality, re-establishing suitable conditions and elevated temperature. Note, there is no mention of specific medicine use with these fishes. If possible, it's best to dispense with any chemical administration, particularly metals, dyes and formalin/formaldehyde materials, as these are quite toxic to the scale-less (naked) pimelodids. In extreme cases of parasitic infestation of ich/white spot or Oodinium/velvet, half doses of medications prescribed for freshwater use and rock/kosher/marine aquarium salt use (a teaspoon per gallon total applied over a period of three days) along with elevated temperature is efficacious. Do particularly be wary of using antibiotics with these fishes, as many such compounds will disrupt biological filtration with disastrous results. Many more fishes are killed subsequent to antibiotic induced ammonia poisoning than from microbial disease.
As catfish families go pimelodids are more susceptible to environmental pollution/disease than most. Ammonia and nitrite will show their marks on these fishes first, as scratching behavior, red markings... and if not corrected by moving them or adding biological filtration, death. An interesting behavior linked with accumulated nitrate is increased "yawning". Nitrates should be kept under 10 ppm. through careful feeding, water changes, use of chemical filtrants...
Nets and Pimelodids Don't Mix:
Many Pimelodid catfishes have stout spines leading their dorsal and pectoral fins, and some of these are branch-spined in turn. For their protection, in addition to reducing the likelihood of damage to the sensory (smell, taste and touch) barbels on their heads, I encourage you to use a technique of bagging them underwater rather than using nets. Barring this warning, be prepared to cut away the netting (not the fish) from entangled fins.
The Pimelodid catfishes are remarkable for their beauty and intelligence, the larger species more like dogs in their behavioral repertoires and learning than fishes. Define your species of desire, investigate its overall ultimate size and provide adequate size quarters, water quality, tankmates and foods and you will have a truly aquatic pet that may live for decades.
Catfishes on the Internet: http://phylogeny.arizona.edu/tree/eukaryotes/animals/chordata/actinopterygii/siluriformes/siluriformes.html
Planet Catfish: http://www.planetcatfish.com/core/index.htm
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