Angelfish dead

Question
Was finally able to add fish to our new 29g tank yesterday (been cycling for a while now). Two small angelfish,6 guppies, and 2 platys. Everything seemed fine this morning, fed the fish and they all ate and seemed fine. Just about an hour ago, one of the two angelfish started darting around the tank very erratically, even crashing into the walls and the gravel. He seemed to twitch sometimes and not swim very well. He floated along the top for a while holding on barely, and finally died. All the other fish (including the other angel) seem fine. Water stats (taken while he was swimming crazy) are as follows: ammonia-0ppm, nitrites-0ppm, nitrates-10ppm, ph-7.4. Water temp is about 76F. The remaining angelfish has seemed timid (he's only about nickel size) the whole time, and we are really worried about him because the guppies/platys seem to be fine. Thank you very much for your time and any information.

Answer
Hi Zack

You added too many fish to your tank at once my friend. Adding that many fish at once can cause your tank to start cycling again. I'm surprised adding that many fish, to that size of a tank, that your ammonia is 0, 24 hours later. Once your tank is cycled, you should only add 1-2 small fish per week until you reach capacity in your tank.

This isn't what killed your Angel however. If he crashed into the walls and gravel, he most likely injured himself severely.

About the only thing you can do at this point is small, frequent water changes (10% every couple of days) and keep an eye on your parameters.

When it comes to Angels, some are shy and timid, others are more outspoken and aggressive. Both characteristics are normal in Angels. Although, the shy and timid ones usually get picked on by other fish, so keep an eye on the one you have. Especially with Guppies who are known to pick on timid fish.

With 6 Guppies, an Angel and 2 Platys, your tank is at capacity. I wouldn't add any more fish to this tank. Unfortunately, you didn't leave any room for scavengers or bottom feeders.

Hope this helps you, good luck!

Richard