Fish acting funny help please!

So ive had the tank for about a month. Bought it used with an existing clownfish. Has been fine i added another clown fish and bicolor blenny almost a week ago. everything has been fine.

I added New heater, New powerhead, StevieTs media rack tonight... didnt rinse them. and then later in evening i notice my fish Barely swimming and hanging out in the cave they sleep in over night. And the older existing clownfish is breathing rapidly now hardly moving at all.. i did a 25% water change and had them in a bucket. for a while

Blenny is staying in his hole and seems to be breathing rapidly also. (from the part of his head i can see)

It is possible that you just scared the crap out of them by doing all that. Just keep an eye on them to make sure

Shes been laying under a rock. I dont think the orange existing clown is going to make it. The b/w i added earlier this week is doing fine it seems

Get it out of the tank, get it into a quiet tank or seperate place with clean quiet water, air, and test your cube water, water change and moving may have stirred some stuff up, and watch how the others do overnight.

Good luck my man.

What are your water parameters? That is the first thing you should check when anything odd is going on

According to the not so great tests that came with the tank when i bought it everything was at an acceptable level. Sorry dont have exact numbers. i have a new test kit otw as i type this.

Orange clown died while i was asleep. Blenny and the black and white clown are okay.

You may have stirred up the gunk when bringing it home and there might now be ammonia. Plus the tests that came with the tank may be old, giving you false readings. I suggest you go get a dropped test kit like API and test it again just to be sure. Keep doing water changes. I"ll have to disagree w/ slim about moving the fish..you'll stress him out even more. Water changes are the way to go.

oh ive had the tank at my house for over a month now.. and all has been well until i added all teh new components i order but didnt rinse them off

Ah. Either way, get a new test kit just in case. I had a test kit that must've been sitting around a while, because eventually, it kept saying I had 20ppm nitrates, when in reality, I had 0 ppm. The opposite can happen.

I lost a blenny in my 10g the day after I added a HOB skimmer. I rinsed it, but I guess not well enough, because up until then, he was perfectly fine, eating, and swimming. It happens, unfortunately.