Lamprologus Ocellatus can't close its mouth

[Lugal]

Hello. I have 3 Ocellatus and 2 Similis in 36 inch x 24 inch tank. White sand substrate with many shells. Using external filter, O2 pump and all. Water parameter is good. Feeding with frozen bloodworm and Tetrabit pellet. They love bloodworm and grew rapidly. 1 cm in 2 week to be precise.

However, 4 days ago I seem to notice one of Ocellatus can't close its mouth. Now to the point it can't seem to eat anything. Yesterday another one got the same symptoms also.

Is it because an infection from frozen bloodworm? Should I stop feeding with it and stick to Tetrabit or brine shrimp instead?

Thank you.

 

[duanes]

Do the mouths seem to extend? And outer lips spread like this?

If so, it is a gram negativebacerial disease called columnaris.

 

[Lugal]

Sorry for the pic, it's the middle one. Its lips seem to extended? If so, it caused by bio-loaded?

 

[The Masked Shadow]

We need better pics

 

[Lugal]

Water change 40% yesterday. No feeding.

 

[duanes]

We need a close up of the face to see what you mean.
I tried to edit your pic to see, but blowing it up just made it more blurry.

If you know someone with a digital camera where you can focus a close up it would help.
Something akin to this amount of clarity. I chose this fish, because it is approximately the same size.