Odd behavior

[Miyavp]

Lately I've caught one of my ryukins hiding under my fake plant, its really odd because its specificly under one leaf and its only occasionally. Other than that all my other fish are acting normal. I have three of them in a 37gal tank. I have an aquaclear 70 along with a sunsun40. I do a ten-fifteen gallon water change every week and I feed them hikari goldfish food along with occasional veggis. Any idea?

 

[Scottyhorse]

Do you have a liquid test kit to test the water?

 

[Miyavp]

Yeah.
PH:7.6ish
AM:0ppms
NI:0ppms
NA:15-20ppms
See levels are good

 

[Scottyhorse]

Seems good to me. Are any of the other fish stressing it out?

 

[Miyavp]

Nope, its bizzare