Why is my clownfish doing this?

[ondy6611]

They’re both hiding under a rock swimming at the bottom and it looks like the mouth is turning pale

 

[Reef Jedi]

How long has the tank been established and what are your current water parameters?

 

[Reef Wizard Steven]

They’re both hiding under a rock swimming at the bottom and it looks like the mouth is turning pale

It looks like you have dinos, and some species of dinoflagellates can be toxic to fish. Based off the video alone, that is my best guess for why they are behaving that way, but I can't be sure. How long have you had the dinos?

 

[Mr. Mojo Rising]

Dino's plus not a single thing is moving in that tank, salt water tanks need water movement. You should have one or a pair of powerheads in the tank.

If you can share a full tank picture, parameters tank age, and filtration folks will be able to help you, but I do see some red flags in that video so I encourage you to help us to help you.

 

[vetteguy53081]

They’re both hiding under a rock swimming at the bottom and it looks like the mouth is turning pale

This is a clear sign of intimidation and not from dinos as the larger clown, often a female is displaying aggression. Separation of the female may be warranted. As for dinos, when we see zero readings, automatically we assume this is the cause but by the time you see zero numbers, its because the dino has consumed the po4 and no3 and are multiplying and in turn many dose no3 and po4 to bring numbers up not realizing they are feeding these flagellates even more.
Its biological deficiencies that are causing the dino structure and Its important though to identify the type of dino for most effective battle. Increasing water flow will also help in your tank.
No light is first key followed by the addition of bacteria to overcome the bad bacteria allowing them to thrive
Prepare by starting by blowing this stuff loose with a turkey baster and siphon up loose particles. Turn lights off (at least white and run blue at 10% IF you have light dependant corals such as SPS) for 5 days and at night dose 1ml of 3% hydrogen peroxide per 10 gallons for all 5 nights which works as an oxidizer. If you dont have light dependent coral- turn all lights off. During the day dose 1ml of liquid bacteria (such as micro bacter 7 or XLM) per 10 gallons. Clean filters daily and DO NOT FEED AMINO OR ADD NOPOX which is food for dinos, however you can feed coral, food which will help no3 and po4 to increase. If increasing nutrients, try to keep no3 to about 5 until you are done battling these cells.
Doing a daily siphoning will help greatly But . . . . . Siphoning will reduce nutrients , so siphon the water into/through a filter sock and save the water and return it back to tank. Obviously clean the filter sock each time.
You can feed fish as normal and if doing blackout, ambient light in room will work for them

 

[Jay Hemdal]

They’re both hiding under a rock swimming at the bottom and it looks like the mouth is turning pale

Looks to me that they are pairing off, but also sparring a bit - that’s pretty common in clowns.

As others noted, I’m concerned about the algae growth and possible lack of aeration.
You should check the tank’s pH before the lights turn on in the morning and again in the afternoon. If the morning pH is low and it rises a lot during the day (say 1/2 to one point) you need to add aeration, not just circulation.

 

[MnFish1]

Looks like pairing. The fish themselves look healthy. Pale mouths come from lip-locking

 

[ondy6611]

They’re both hiding under a rock swimming at the bottom and it looks like the mouth is turning pale

Looks to me that they are pairing off, but also sparring a bit - that’s pretty common in clowns.

As others noted, I’m concerned about the algae growth and possible lack of aeration.
You should check the tank’s pH before the lights turn on in the morning and again in the afternoon. If the morning pH is low and it rises a lot during the day (say 1/2 to one point) you need to add aeration, not just circulation.

I recently cleaned it off as best as I could and it grew back really quickly and there’s a bubbler in the overflow reservoir

 

[Jay Hemdal]

The pH method will tell you if your aeration in the overflow is sufficient. You can buy a pH pen on Amazon for $10 to $15