may have sick fish???

so i have a question. one of my fish a yellow headed sifter goby. is acting strange he wont come out of hiding unless it is feeding time not sure if he is just acting strange or if he is getting sick any advice will be appreciated.

 

did you just get him?

 

no i have had him a cuople onths now. he has always been shy and would hide when someone would walk up but if you sat there for a min he would come out and swim around. now he hides in the corner under my rock and dont move unless it is feeding day

 

how are your water parameters? could anyone be picking on him?

 

my param are all good i just did a 5 gal water change. in my 55 gal. i dont think anything could pick on him he is the biggest one in the tank except my clown fish might be able to they will nip at me when i stick my hand in so maybe i am underfeeding them but i doubt they pick on him

 

we need real params not just it looks good.

 

also i have seen 1 inch damsals pick at a lion fish... size means nothing

 

i will get them again in just a min. i was reading on dieses and i was reading about mouth rot and my fishes mouth has turned white and used to be yellow all over is that anything

 

nitrate 0
nitrite 0
alkalimity 180
ph 8.0

 

he died other fish are still doing very well