Possibly sick guppy and ? about a banana plant.

[ForestLazer]

So I've got a new tank that has been set up about 2 weeks now. I've learned the hard way about cycling, so I've been doing water changes every other day. I've had this yellow cobra guppy a bit over a week now and it's tail is beginning to shred. The fish seems to be losing it's color and it's tail is almost translucent. I thought maybe my other guppy was nipping it's tail because it nips at my molly's tail, but the guppies tail doesn't look nipped. It looks shredded. It also has started to get a reddish brown spot by it's tail. I've posted some pictures, sorry they aren't the best quality. My phone sucks.

I also have a question about my banana plant. I think it's dying, but I'm not sure. I posted a couple pics of it as well. Is it dying? Should I remove it from the tank? When I check the ammonia levels it's usually at .25 and I'll do a 25% water change. It was at .50 this morning so I just did a 50%(probably a bit more) change before taking these pics. Any help and advice would be appreciated!

 

[Angellove78]

Could be worms. Banana plant looks alive, just got some algae on it.

 

[ForestLazer]

Worms? Is that something that the other fish would get? What do you do for those?

 

[Angellove78]

Yes, the other fish can get them. Treatments to check into, but some will leave a blue stain on the silicone of your tank, and air hose. https://www.thesprucepets.com/external-fish-parasite-treatments-2924995