Please help my talapia stopped eating

my 12 in talapia stopped eating and my vampire tetra has a disease the tail is turning white and fins are torn

dont know why anybody seen before

Sorry to hear of some fish issues. If you get a chance, can you post a picture for us? My guess based on the description of the tetra is fin/tail rot? there are numerous medications that are made for this. i do not know which one works the best, as I haven't personally experienced it. I'm sure someone has dealt with this before, and will chime in shortly. As for loss of appetite, can you share your water parameters? I wonder if something is out-of-whack with the water...... if you can post results, we could steer you in the right direction.

With the tilapia I would also would watch the fish poo and see if it is white and stringy. Might be an internal parasite issue that you might need to tackle with Prazi or Tetra Parasite Guard. But usually my first thing is exactly what Lloyd recommended, and that is to pull out the test kit and check your water. Usually if anything just do a few small water changes over the next couple days. Surprising what clean water alone can accomplish.