Clownfish stopped eating two days in a row

[Fishlover56]

Hi
my clownfish has stopped eating for two days now he my only fish tank my damsel recently got attack by a birstleworm in his hole but in the last to days i have gone from a canister to a hob filter i transfered the media over also i have had a rework of the rock work.

my clown fish looks physically healthy swimming fine his breathing rate has slightly increased i have watched this over the two days and it hasn't got worse
my levels
ph 8.0
ammonia 0-0.25 according to the api test kit
nitrites of the scale im doing more water changes and leaving light off longer to stop algae grow and to hopefully reduce nitrates thats why i have change the canister
salinity 1.026 im trying to get an ro unit but i just use dechlorinated tap water right now
temp 78
i just have one clownfish in a 15 gallon the tank is a year old and i did cycle it fishless Before add fish

my guess is that changing the Filter which creates Different flow and moving the rocks Has caused stress
then i don't know if nitrates have an effect on the clown
if you have any advice or guidance pls let me know
many thanks

quick Edit : i have pointed my wavemaker to the surface to help with oxygen exchange if thats the issue

 

[Fishlover56]

Sorry its on the wrong one