CichlidFish.com - Fish That Think.

I have a few aquariums that together hold 2 tiger oscars between 3-4in., 1 tiger at about 2 in., 1 green terror at about 2 in., 4 bala sharks 3-4 in, 2 african brown knifes between 6-7in, a black ghost knife at 2-3in. and a common plecostomus at about 6 in. I bought all these fish when they were quite small and had them together in a 75 gallon, but as they grew up I separated them since the 75 gal. couldn't contain their combined size. Now I'm planning on purchasing a 300 gal. and am curious if I can reunite the group in the 300 gal. habitat. I'm not worried about fighting cause I know they get along, just whether 300 gallons is large enough for all of them.

No guarantees of course -- the fish make up their own minds about whom they'll get along with, but I see no reason why those fish shouldn't be just fine in a 300g aquarium.  What are the dimensions?  Floor space is important.  More square inches of floor space is more important than pure volume of water.  As they all get larger, you'll want to be sure that black ghost has adequate hiding places.  The GT will also be happier with a shelter or two.  I'd say go for it!  Welcome to the forum, and keep us posted!

The particular tank I was looking at is 96x24x30. I'm not too worried about them getting along though. I've seen them interact before and they're all pretty docile, even the GT. And I won't fill their former tanks with new fish till I know that everything is working out in the 300 gal. The main reason I'm getting the new tank is because right now I have the 3 oscars in a 75 gallon tank and I think they've outgrown it.  If everything works out I plan on making the 75 gallon a GT species tank. I know they're aggressive, but do they get along in groups or should I have 1-2 at the most?

With cichlids, sometimes 3's a crowd.  If 2 of them pair off, the odd man (fish) out is likely to get beaten up.  2 GT's could easily get along in a 75.  Once they mature though, 3 would be pushing it.  Maybe have something else in there with them, possibly even a non-cichlid, like a group of giant danios, silver dollars, or clown loaches. 

Well, looks like its not going to be a 300gal after all. It's going to be a 240 gal, with a wet/dry system complete with bio-balls, a canister filter, a uv sterlizer, the whole thing so I'm still not worried about the bio-load. One of my brown knifes died. He never got any food, lousy oscars eating anything that touches the water. Anyway, a 12 in clown knife will be filling his spot in the new aquarium. He will be the only knife fish in that aquarium,  no worries. I just figured if I'm going to have a knife fish with three oscars it better be one that can fend for itself and manage to get itself some food. I'd appreciate any further input. The new plan is 3 tiger oscars 4 bala sharks 1 pleco 1 clown knife and of course my gt beast in a 240 gallon.

wow thats still a huge tank ! People must have huge houses in the USA to be able to fit such big tanks in. I am having a new 5 foot tank ..100 gallon.. and I thought I was going up in the world lolll. Good luck with that. You are going to need a scuba set to clean it loll.