Any Knife Fish Suitable For A 20gal?

[Neal]

I really love GBK's, but I only have a 20Gallon, my brother keeps his in a 15Gallon but I don't want to follow in his steps, is there a certain type that is quite common, relatively easy to look after and fairly cheap?
The tank is 20 Imperial Gallons, the measurements are 30"x15"x12"
Thanks in advance,
Neal

 

[AMS]

A tank that size is just too small for any knife species. The only knife species that would come close would be Apteronotus leptorhynchus which usually will not grow past 6.5 inches in aquaria, but has the potential to reach 15 inches. Apteronotus leptorhynchus is a difficult species to find also.

 

[OohFeeshy]

There are quite a few small species, although most aren't overly common. African brown knives stay quite small, although they might be too big, but if you're willing to go for some harder to get things, theres the
thermometer knife-Gymnorhamphichthys rondoni, or Mottled knife- Steatogenys Duidae. The first is probably easier to get, and is very nice.