Originally Posted by allaboutfish
It's 48x24x24 and I was on that site and am a active member on a sister site of theirs and I know they care about fish.
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I've been there and seen the kind of garbage "Info" they give to first time or anticipating poly keepers. They advocate things like overstocking tanks which leads to aggression issues, allowing for no hide spots to prevent aggression because they already keep too many animals in one tank...and I saw how they tried to encourage a first time to overstock a 75 gallon with multiple bichirs and ropefish.
Sorry, it is what it is that you are not likely to get good advice from a place like that. If you want your fish to be happy, and for you to not have additional unnecessary expenses down the road please listen to those who truly care.
I personally would not suggest keeping even rope fish in a tank the size of what you have. These are fish that can get easily 2-3 feet or more and need to have multiple members because they are social fish. Think about this. You want to put a fish that stretched out is 3 feet long in a tank that is 4 foot long that is also 2 feet wide? It cannot go one foot without bumping into a wall and when full grown it's going to be interesting trying to move in a tank when you are constantly hitting the sides.
I understand you really want to keep these fish the Bichirs. But they have certain requirements including the rope-fish. What you can do is go with one of the smaller species of bichir but make sure that any fish you get have an adult length of around 5-6 inches at least. Feed your bichir on only pre-killed foods and ensure it has it's own hide spot for when it wants to get away. Pay attention to your bichir as it starts to grow up (get it young). If you get some floating plants for the top of your tank the bichir should be able to find that and use it to float and get easy access to air.
You could also get something like a 20 gallon long and use it as a temp grow out for the bichir if you are worried about it having too much difficulty getting air access in the big tank. Only get one bichir. A tank your size can easily see aggression issues because bichirs like having a lot of space to themselves.