Missing Otos

[LKH]

OK, I have a densely (and I do mean densely) planted 10 gallon, formerly inhabited by a single male betta. Last weekend, I bought 5 otos to put in his tank. I know, that's a lot for a 10. I was thinking about how they like to be in numbers, and how, if he got the urge to pick on them, larger numbers would mean no one fish got the worst of it.

Anyway, I'm kind of used to the fact that otos have a way of disappearing into the woodwork. It's rare I see all five in my 30 gallon. So this week, the fact that I didn't see all of them didn't particularly alarm me.

Yesterday, I found one of them dead, caught behind my $*#()@%#&* Hagen bubble ladder (wasn't there the night before, so this happened overnight). And then there were four.

Tonight, I had some time to kill, so, I pulled a stool up and just turned out the lights and watched the tank. And watched. And watched. And I can only find two of the little buggars. They're happy, swimming around, doing the little circles around each other the way otos do. But the other two are gone without a sign. I checked the filter. I looked every place I could look without tearing the tank apart. I felt around behind the fake driftwood. I can't find any place they might go where they could get stuck.

Tank parameters are good - nitrates under 10, nitrites 0, PH about 7.2. The ammonia sensor looks good.

So what should I do? Should I tear the tank apart to find them? I know otos are fairly tough to acclimate to a new tank, so they may have simply passed away over the week, and because they're dark, and my gravel is dark, they're just not that visible down amidst the stems of all the plants. Should I just keep watching the water quality and doing water changes as needed?

L

 

[TCTFish]

Senseless to tear down the tank and subject everything else to some serious stress. Plus...does not guarantee you will find them...even if they are still around. I've torn down a tank to look for eels that were 7" long and never found them...and the tank was empty of water. After putting everything back together...there they were!!...LOL.

I'd say if you don't notice the fish in two weeks...then most likely they've become part of the substrate or filter debris. I highly doubt the betta would do much being otos are well armed against small fish that try to take a bite. Their entire bodies seem to be covered in little spines. Doesn't mean a betta can't do any harm, but the chances are unlikely.

 

[LKH]

Thanks! I guess I'll just watch the parameters closely and if amonia or nitrites spike, then I'll think about tearing down the tank.

You're right - the other fish have been stressed enough. In fact, the latest addition is a poor little cardinal tetra who has some kind of spinal deformity. He was part of a school of 10, but the others keep tearing up his fins, so now he's a loner in this tank. He's been moved more than is healthy already. I put him in QT in December for 2 weeks, and after he healed up, put him back in the 30, then saw they were picking on him again, so back to the QT for another week of Melafix, then to this tank. He would probably be better off if he could stay put now. And the otos, obviously, are new, so they've had a bit of stress as well.

I wasn't so worried that the betta would hurt them as that he'd heckle them to death. He was initially in my main 30 gallon tank, but he got a bit nippy with the otos there and started flaring at the feeding ring. I knew that otos would have no problem evading him, but I didn't want him wearing them out, and with five targets, I figured that wouldn't be so much of a problem. As it turns out, he pretty much ignores them.
L

 

[Andos99]

Strange little fish indeed! I have 4 myself in a 10 gal and I will go a few weeks without seeing them all. One here and one there is common, but all four is rare. Every now and then I'll throw in an algae wafer and check back in an hour and they will all usually be together eating away. Sometimes I swear I only have 2 left, but if I look hard enough I can usually find them all.

 

[LKH]

I've kind of gotten used to not seeing all of them when I do my nightly head count. But generally, if I sit and watch and am patient, I will eventually see most of them. I actually haven't seen more than two for several days. Doesn't mean the other two can't be hiding somewhere, or I'm seeing two different ones each time I look. But I kinda suspect that I have a couple of casualties somewhere. I hope they're not stuck somewhere I don't know about. I kind of felt around looking for holes they might've got into, but couldn't find any.

L