longfin blue dainos, community?

[auxout]

Ok once again one of my fish has dissapeared. This is getting old I just can't figure it out. Every dang type of fish I try either won't grow or are supposed community fish and turn canibal and aggressive. Right now I have a 20G long with 2 longfin dainos, 2 scissortail and 2 ottos. It's been going probably close to 6 months with no problems. But just this week one daino dissapeared and the other one who has always been slightly agressive has turned super agressive. Not so much biting but just chasing everything around, doesn't make for a very nice tank. So I have 2 questions.

#1 What should I be feeding these guys to get them to grow some? or are they just real slow growers? I realize the ottos won't grow much if at all, not worried bout them.

#2 Did I get faulty info, dainos = bad community fish? Or did I just get a bum fish?

I'm about ready to buy a huge tank or dig a 5000 gal pond in my backyard and make a local species pond. Had a chance to take any size fish recently but missed it, they were draining a DNR lake and all size limits were off.

[OrionGirl]

Just my experience, but the 'other' danios--ie, anything but the standard zebra danios--tend to be shorter lived and less hardy. I started out with leopards and zebras, and even though eveything else was thriving and the tank was in good shape, the leopards slowly developed hunched backs and died within about 6 months. The zebras were thriving, so I picked up some pearls. Same pattern--and the zebras continued to thrive.

As for aggression--I think th elittle buggers need to chase something around. Not sure why, but mine would chase anything that got in front of them. Never did any damage, but this was on of the reasons I've decided not to get any more danios. I don't think they are bad community fish, they just aren't good with slow moving fish, like gouramies, neons, etc., IMO.