The "monster fish" is a toadfish, there are several brackish ones but I think that one is the river toadfish, Thalassophryne amazonica, and it is a sedentary ambush predator, it gets to around 6" and has recently been tank bred, it is a true freshwater fish, because of their habits they a pair can be kept in a 20g tank, they prefer a sand or fine gravel bottom as they like to partially bury themselves. They also prefer live foods but can be fed by using a food stick to wave meaty foods just above their heads. There are several reported hospitaliztions due to stings but no reported deaths, the venom is apparently very painful but not life threatening.



