Lost first fish today

[gnasher]

Hi everyone. I lost my first fish today and just wanted to check with you all to see if there was something I could have done differently to have prevented this.

The tank is a 40g FOWLR with two damsels (domino and jeweled) and a mantis shrimp. I also have another ill behaved damsel temporarily living in the fuge. Last night, I installed a Koralia Hydor 750 to increase flow in the tank. I pointed it at the rockwork and turned it on. It stirred up some detritus, and the fish were a bit startled by it, but no more than I had seen from other things, like me sticking my hand in the tank. I turned the lights off for the evening to help them settle, and noticed them both calmer before going to bed.

The only other thing different about today was that I had to drive a friend to the airport and woke up at 5:00am and turned my room lights on for a few minutes. I noticed the jeweled damsel doing his usual "confused that the sun is out" dance near the substrate. Don't remember whether I saw the domino.

When I fed the tank this morning, I found the domino laying on its side behind the rockwork with its mouth wide openn, gills flared, and body stiff. Its body was pale, but I've seen it look like this at night before.

This was my favorite fish and the most well mannered one of the three I owned. He did get his fins nipped from time to time, but held his own and I wouldn't call him "bullied". The tank is 6 months old, and I've had the fish about as long. Water parameters have been kept very steady at values below, which I just measured again. I got the tank used, and nitrates used to be MUCH higher, but they've been steady here for the past two months at least.

SG = 1.024
amonia = 0
nitrite = 0
nitrate = 20 ppm
temp = 80F

So, could I have stressed my fish to death with the powerhead? Lights on a bit this morning, maybe helped with that stress? Could exposure to higher nitrate levels earlier on and/or the current 20 ppm have done this? Maybe the occasional scraps with his roommate got to him? Any ideas would be appreciated.

 

[cjk76]

You were playing with fire putting fish in with a mantis shrimp. Also, they were damsels, which are notorious for being bullies and killing almost everything you can put in a tank. The detritus could have added nitrates to the water, but I doubt that was the main problem. I also turn my lights on occationally and my fish don't seem to mind. You had a couple of aggressive fish in the same tank with a mantis shrimp. Losing fish is an eventuallity with this setup. There are exceptions, but you wouldn't want to chance a walk down a street full of bullies. Why would you put a fish in that situation?

My suggestions would be to:
1. Remove the fish to a QT, if you have one (or throw away the dead fish).
2. Figure out what type of tank you REALLY want (Mantis, Reef, Fish Only, Damsel).
3. Remove and sell the innappropriate species.
4. Research the best environment for the view you want and start building it.
5. Buy more than just a nitrate/nitrite test. Phosphate, Alkalinity, and pH are also important.
5. If you are still worried about the light, buy a lamp with a softer glow to put in the room.

 

[gnasher]

Wow, thanks for that.

My mantis is a smaller smasher and completely ignores fish. Yes, I know damsels are bullies, but like I said, I don't think that was an issue with these, the only two fish in a 40g with lots of rockwork. It was an issue with another one I had and I dealt with it appropriately by setting up an entirely separate tank for it.

I know those other tests are important, that's why I have them and take those readings as well. I didn't think my phosphate levels were pertinent to the thread, that's why I didn't include them. You could have just asked for them if you wanted them.

While I appreciate at least someone responding, I started this thread because a fish died prematurely and I was looking for some insight as to why. I gave a few details of recent activity in and around the tank to help. It certainly wasn't mantis violence. I don't think it was fish violence as I hadn't seen them even fight in the past few weeks, but I'm open to that possibility. That's why I mentioned it.

 

[aleonn]

It could be possible that stirring up all that detritus led to a small ammonia spike, which would have cleared up by the time you tested for that parameter.

I think it's more likely that your fish got confused from the new water flow, and strayed into the mantis' territory inadvertently.

 

[gnasher]

Thanks for your input aleonn. I know it wasn't the mantis because he lives in a rock, he only uses one door, and it was sealed from when I turned on the powerhead to when I found the fish. It hadn't been opened and then closed again either, as it looks different each time he does.