Can a fish knock himself out

[Bigge_al]

I have a dalmatian molly that when I feed them this morning he swam so fast to get to a piece of food he hit a decoration and it looked to me he knocked himself out. He went belly up and then he slowly started breathing again then he righted himself and swam off and hide for about 20 min. Now he is acting normal swimming with his other mollies now. This is the same Dalmatian Molly that was being aggressive yesterday.
I had a black one I returned yesterday that after I feed the tank i would find him belly up and then he would be fine but I thought that this was weird so i took him back and got another black.

Is there something I am missing that could be wrong with just mollies. Could it be the food.

 

[George9]

I don't know If they can knock themselves out, but they can definitely hurt themselves. One if my fish almost jumps out if the tank for food an splashes me lol

 

[Nu-Nu the eel]

Hahaha i can just imagine a huge molly running right into a decoration. Lol...

I hope hes ok

 

[RedFlame]

Reading this thread has made me realize I am an odd person, I imagined your molly with a head bandage. I hope your fish makes a speedy recovery.

 

[Bigge_al]

I am sorry to report he commited suicide. I found him about 20 min ago.

 

[George9]

Lol
sorry it's not funny sorry for your loss

 

[Bigge_al]

I am sorry to report that I lost two more mollies to the same thing. They went crazy and died. I went to a professional aquarium store and asked there fish expert and he had no idea. The conclusion is that they came from a bad batch that had some neurological issues. I have one black molly left that came from a different tank he seems to be fine but is showing a little shyness. My single neon tetra has great color and seems to be healthy.
We have decided to hold off on anymore fish for 2 weeks to see if any other issues come up.

 

[Coryluv]

I'm sorry for your loss. It is always hard to lose those little finned friends of ours.

 

[absolutangel04]

Assuming you have a proper sized tank with good water params, then yeah, it could be neurological issues IMO. Sorry about all your fish though!

 

[Bigge_al]

Today I lost my last molly I saw nothing indicating he was having problems. I did do a gravel vac yesterday but I do not think that it had anything to do with his death.

 

[adadkins1]

Very sorry to hear about this. Mollies, from what I have read, can be touchy fish if not kept in pristine conditions. This seems to be more and more true as fish farms continue over breeding.

 

[absolutangel04]

Sorry about your fish.

 

[Copachick]

I don't know If they can knock themselves out, but they can definitely hurt themselves. One if my fish almost jumps out if the tank for food an splashes me lol

My Bleeding Hearts do that, lol. and theyve gotten so big Im afraid they actually will jump out. They'll splash me in the face alot

 

[meegosh]

What are your water parameters? With that many dead fish in such a short amount of time I bet you have a spike in ammonia. Did any of them have any signs of disease? Sounds like flashing to me, rubbing against objects in the tank.

 

[Bigge_al]

My parameters are:
Ammo-0
Nitrites-0
Nitrates-30
pH-7.4

I am not seeing problems with any other fish in my tank only the mollies died.

 

[absolutangel04]

30 nitrates is a bit high IMO. I suggest you try to keep it a little lower if you can. But, its not exactly astronomical or anything.

 

[Bigge_al]

Yea I did a 60-70% PWC this morning. I retested and I messed the test up last night the actual Nitrate level was closer to 60ppm and my ammonia level was .25ppm. Even with the PWC the nitrate level will still be in the 20's since my tap water has nitrates in it.
I also notice that one of my oldest fish had a stingy poop so I threw in some peas and he jumped on them. If I see anymore stringy poop I plan to get some internal parasites medicine. Since I have not seen any stringy poop B4 last night and I have not added any fish recently my first assumption has to be constipation not internal parasites.