Have you got any pics?
Hmmmm, that sounds ominous, does it look like a smaller version of this http/www.planetcatfish.com/catelog/bagri...mibagr/19_f.php or this http/www.planetcatfish.com/catelog/bagri...ibagr/801_f.php or this http/www.planetcatfish.com/catelog/pimel...actoc/305_f.php
These are all known as redtail catfish in the trade, the first two are from Asia and are well known for their antisocial behaviour toward any other living creatures, the third is the South American redtail which is a peacefull fish but grows to around 4 feet and will eat anything its mouth fits around, including heaters, filters and ornaments.
Holy smeg! Got yourself a right one there. Wish all the luck in the world. *Looks happily at her small slow growing cats who are so docile they don't even chase platie fry. *
Hugs,
P.