This was written by Mod. CFC:
Elephant nose fish
Often sold incorrectly as elephant nosed catfish elephant nose's belong to the Mormyrid family of African fishes. Most species in this group have a week electrical organ which is used to find food and defend their territory from other elephant nose fish, this abilty has been utilised by some water companies as a early warning of poor water quality as the fishes electrical activity increases with stress. These fish are usually sold as good community fish which is unfortunately not true, not only are elephant nose fish territorial but they are also very difficult to feed in a community setting as they cannot compete for food due to their tiny mouths, many elephant nose fish die from starvation. Another problem with keeping these fish is that all Mormyrids are highly sensative to copper based medications which makes treating for ICH and other common aquarium diseases almost impossible in tanks containing elephant nose fish.
Gnathonemus petersii, Peters Elephant nose; By far the most commonly seen of the Mormyrids this fish is territorial and may be aggressive to its own kind, either keep them singularly or in a group of at least 5 with 20 gallons of tank per fish. Like all Mormyrids they require small foods such as bloodworms and tubifix worms and a soft sandy substrate to prevent damage to their delicate mouths. Water quallity must be excellent at all times. A tank of 55 gallons or more should be used as the fish can grow to around 9 inches.
Campylomormyrus tamandua, Long nosed Elephant nose; Not as common as Peters Elephant nose the longnosed elephant nose is very aggressiv to others of its own kind and should only be kept alone or with other large but non aggressive slow feeding fishes. They grow to around 15 inches and so need a tank of around 100 gallons to be kept properly, as with other Mormyrids water quality needs to be excellent at all times.
Petocephalus bovei, Baby Whale; This Mormyrid lacks the "elephant nose" and so is not as easily recognised as the last two. They are seldom seen in the trade only being occasionally imported from West African exporters. These will grow to around 4 inches and like other Mormyrids are territorial amoungst their own kind, if kept in a group keep only one fish per 20 gallons of tank volume. Care is the same as other elephant nose fish with small foods, sand substrate and excellent water being required at all times.