Climbing pearch and interesting remind me of small Danoids. African butterfly fish have a neat body shape like a mini arowana with wings, rope fish and several spiney eel species would also do fine in a tank that size. Actually you could mix most of the species i mentioned together in that tank and have a "mini monster type setup"
Also if you go brackish there are some interesting puffer species, puffers are very interesting fish too keep . small pike cichlid species are another interesting option I could go on lol LOT's of choices.
Also if you go brackish there are some interesting puffer species, puffers are very interesting fish too keep . small pike cichlid species are another interesting option I could go on lol LOT's of choices.