Could I fit a marbled bichir in a 30 gallon? Are there any compatible tankmates? Also would a knife fit in and are there two different sorts because in the book it was grey, at the shop it was black with a white stripe and looked much more interesting
Short answers, no and no . Both these fish will quickly outgrow a 30g and have a maximum size of over a foot, a 75 gallon is the minimum recomended size for either fish. Both fish are predators so tankmates need to be at least 3/4 their size.
