Lost 3 new fish

[Brandon K.A]

So long story short, after a long tank cycle, I added a firefish to my 29 gallon tank. I had aquired him from petco. When I put him in, he was a little shy at first.. but would come out every so often. About a week later, I added two clowns and a scooter Blenny. They all seemed fine. then a few days later, I noticed the blenny had disappeared. Then about a week later, my smaller clown had died. It just laid there, next to my firefish. It was just frozen dead.. I noticed no markings etc on him. Then within the few hours, I noticed my firefish had a brown spot on the side of him, and he later died. The only fish that is now left is the bigger clown. He has been eating fine and swimming fine for a few weeks now. When I tested the water when the deaths occurred, there were no discrepancies. The temp is a little high, in the 82 range. Did not yet do a water change.

Not sure if this is related, but i think I have a small mantis shrimp in my tank. Always hearing a clicking noise during the day, and I actually removed a piece of live rock and got rid of one or two of them that I saw in there. But apparently I have another. Not sure if they have anything to do with the deaths. These shrimp were very tiny not even an inch in size yet.

I know it is really late to be asking for help, but have been really busy lately. Although that is no excuse for the well being of my fish.

I notice my only fish left is my clownfish. He has been eating well, and swimming actively. Currently it is 2:35 am and he doesn't seem as active. Could be he is sleeping? He is about an inch and a quarter. Thanks for the read.

 

[Brandon K.A]

A picture before he passed.

 

[Brandon K.A]

A picture before he passed.

He only looked all beat up like this in the course of a few hours. Before I went to bed he seemed fine from what I could remember, no torn fins etc. Then this happened when I seen him next.

 

[barefootbc]

Would love to hear some insight on this. I have lost 4 fish now in similar circumstances, water parameters are fine. Haven't looked for any suspicious markings as you described.

But I do hear clicking noises all day and I do not have any pistol shrimp. Have not seen the mantis.

Is this something they do? Randomly kill fish but not eat them?

 

[Breakthecycle2]

By guess is a small mantis shrimp or serpent star perhaps.

 

[Ingy]

"When I tested the water when the deaths occurred, there were no discrepancies"

What does this mean? What test kit are you using (not test strips I hope)?

"Did not yet do a water change". Did you do one after the cycle was completed?

Post your water test results.

Fish DO sleep at night.