Help Sick Swordtail?

[Katkatt]

Does anyone know what’s wrong with my swordtail?

I’ve been really busy the past couple of days and out of house (entrusting my fish feedings to my lovely mother) and I recently finished setting up my 55 gallon, which has four sword tails, three adult guppies and about five-seven baby guppies, around three mollies, and four corys (plus snails and shrimp)

When I checked on my tanks today (since I passed out after getting home last night) and I found one of my pitch black female swordtails looking like THIS

I immediately set up a 2.5 quarantine and popped her in there, but even beforehand she still has a food drive (though she was sat at the bottom of the tank and has a really jaunty, frantic swimming style)

help????

 

[Rancore]

Have you tested your water?

It’s very common when getting other people to feed your tank, they mistakenly overfeed them. This can spike ammonia levels and lead to numerous other problems.

I suggest testing your water parameters, and posting the results back on here

 

[Mcasella]

Are you sure that is a swordtail? It looks like a golden lyretail molly, did your mom buy a fish and stick it in your tank while you were gone?
Black swordtails do not lose color like that and turn the peachy orange of a molly.