One fish is spazzing out

[ImBettaThanCool]

Before you read, note:
40 gal fish tank
Every other week water change
1 angel fish about 2 to 2.5 inches in diameter
3 Mickey mouse platies
2 zebra danios
Mediumly? Planted(don't know how to describe but it's in between heavily and lightly)
Tank has been running for more than a year. Some fish have died, and some new ones have moved in

The problem is with the angelfish. He's one of the seniors in the tank, along with the two remaining zebra danios. Now, he's been in the tank for a solid 7 or 8 months now. I've lost many fish since then, but he stayed strong throughout everything. So I thought I had absolutely no problems. But then, recently I added 3 Mickey mouse platies. I had Mickey mouse platies in the tank before, so I knew they were compatible, so I wasn't worried. I also knew that the tank was fully cycled and there was a hefty amount of plants, so I wasnt worried about overpopulation.

But then suddenly, the problem arose. About a week after adding the platies in, my angelfish started to spazz out and just randomly jump out or dash to the other side of the tank. This got me worried. The thing is tho is that no other fish in the tank did this. The angelfish I thought was the toughest one, seemed to have become sick. I don't know what's going on, so please help.

 

[Autumnsky]

And what are the water parameters right now?

 

[SaraB]

Try doing a weekly water change routine for a bit and see if it helps.

 

[Allisonm24]

See if zebra fish and angel fish have diseases. I would maybe remove the new Mickey Mouse platies and put them in a different tank. Obviously they are stressing your fish out and have made them sick. So take them out and treat the sick one too.

Once you remove the Mickey Mouse Platies observe if the zebra fish becomes more relaxed like he did before. This happened to my fish. It takes a couple days for them to combat stress and get healthy again, but you need to remove the Mickey Mouse platies and see if that makes it better. Definitely brought a disease to the tank & stress.