African fish losing weight

[helptoall]

Hi, this fish has been rescued a few weeks ago from a neglected tank. when we moved him we made a mistake with the water temp and he experinced a sudden change of around 2 degrees C in a few min. since then he became very pale and started to lose weight. He is active eatign and swimming. He is in a 100L tank by himself with a filter, temp is 27 and theres aretation. Water P are 0,0,10.
Ive already tried treatment with Levamisole and praziquantel for parasies.
What do you think this could be and what do you reccomend? btw can you identify the fih? i just know hes an african ciclid and im pretty sure his a peacock.

 

[lazarusthefishboy10]

It looks fine to me, but maybe I'm not seeing it properly. It could be an internal parasite that eating away in it, and eating all the food it eats. Get @Colin_T to tell you how to treat internal parasites, mate! Good luck with your fish! He is a gorgeous little one!