I tried a giant danio, thinking it would get along with the other zebra and longfin danios in my tank. Wrong! As soon as I put the giant danio in, he immediately started chasing the smaller danios all around the top part of the tank. The only place the other danios could get away from it was the lower part of the tank, not the place zebra danios want to be. Anytime a smaller fish would try and get up to the top, the giant would nip at at and chase it. I lost two zebra danios overnight, their fins were shredded and the giant didn't let up on his aggression, so I returned it to the store. Good riddance! Almost all other species I have introduced into my 200 liter community tank have gotten along, but never will I put one of these fish in again! Maybe several of them would be calmer.
I purchased 20 of the Giant Danios for my 200 liter tank and found out that, unlike if you just had 2 or 3 where one can bully the others, there is too many for just one to bully. They are doing great and are even spawning.
I have a 75 liter high community tank with 5 giant danios. In contradiction to the letters posted, they are great tankmates. I have not had a single problem with them being aggressive. The tank contains 4 black tetras, two serpae tetras, two gold barbs, two platies, an albino cory, and two black neons. I love the danios, they are very active and very attentive to anyone close to the tank.
I have 4 giant danios in my 180 liter tank, along with 1 penguin tetra, 2 dwarf gouramies, 2 mollys, a red tailed shark, a common pleco, a ruberlip pleco, and a bamboo shrimp. My Danios are my most recent addition along with the ruberlip. They really add a lot of entertainment to my tank. The tetra always hangs out with them and they are never aggressive to each other or any of the other fish. They always swim to the other end of the tank whenever I come by. They also go nuts when I clean the tank. I really enjoy my tank now that I added them.
I purchased three giant danios back 6 months ago along with a couple of cherry barbs and a Goldfish to put in my tank. I also had some other fish like zebra danios in my tank. At first I really liked the Giant Z's as they added some color and movement to the tank. But some of my excitement ended when they bullied the life out of my Goldie who I really loved and picked at other fish. I don't know what to do with these fish because they're all healthy as horses. I would not recommend these fish.
These fish seem to drive some fish crazy because they aimlessly go back and forth. I had about 5 of these, one was a little shorter than the rest (midget). These fish would swim to one side of the tank and then swim to the other non-stop. It got on our nerves so much that we gave all of them away to a local pet store. I do not recommend these fish to anyone who wants a peaceful community tank, but to those who want to watch fish go back and forth, this is your fish.