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[aerofish]

I have a 15 gal w/ 2 zebras, 2 platies, 1 black molly, 1 silver molly. Yesterday I bought an angelfish and a bala shark. The shark is about 3.5 to 4 inches long and I only bought it after I read hundreds of reviews saying that it is peaceful and can live w/ smaller fish.
The problem is I cant see my other fish anymore. They are all ganged up at the very top of the aquarium right under the water surface, not active at all. Only the zebra danios are swimming around...and of course the shark which seems to have dominated the whole tank.
I never saw the shark be aggressive toward any of the fish. What is going on? Are the other fish simply afraid of its size? Is it better to get a smaller one?
Another question: Only after I bought the angelfish, I found out that it likes to "pair up." Can I pair it up w/ another angel that is the opposite sex but does not have the same colors??? My current angel is yellow and I have no idea what sex it is. Please help...

 

[Silly me]

wow ppl are going to cut you head of for putting the bala shark in a 15 gal...

uhm the 15G is also to small for the angel, localy angels is the cheapest fish so I see lots of the in small ( 10g - 20g) tanks.

But the Bala shark will get aggressive in a tank smaller that 75 Gallon and even more when they are alone... Getting a smaller one will only pause the aggressive behavior till it get bigger.