Danio Acting Strange

[luckyd]

We have five danios in an established 34-gallon tank that has been operating for several months. I'm sorry I don't have water parameters right now but I can go to the fish store to get them if need be. One of the danios has been acting strangely for the past 2 days. Yesterday, he appeared to be backing up to the intake grate for the filter over and over, then "swimming in place" against the current. It looked purposeful but it could be that he was being sucked toward the grate and trying to get away. This morning, he picked a spot toward the bottom of the tank behind a cave and is swimming back and forth in the same spot. But when I opened the tank he rushed to the top, then joined in with the rest for a little fish flake snack. As soon as I closed the tank, he went back to the same spot near the bottom and started the back and forth swimming in the same spot. He almost looks anxious when he does this. Occasionally he goes back to the top and swims against the intake flow again then goes back to the bottom. Does anyone have any ideas on what could be causing this strange behavior and what to do? I'm afraid there's a second one that may be starting up the same behavior. Thanks for any help you can give me.

 

[WILDER]

Do you only have the danio's in the tank.

First thing we look at is water quality.
Take a sample of your tank water to the lfs and ask them to write the readings down for you.
I would strongly suggest you invest in some liquid test kits of your own.

Is the fish gasping, or darting around the tank aswell.
Make sure the current of the filter not to strong and blowing the fish around the tank.

 

[luckyd]

Thanks. I will try to get the water tested in the next couple of days.

The danios share the tank with 2 male platys, 1 DoJo, one young (& so far peaceful) golden algae eater, and 3 corys. The only new fish is the DoJo, which we got in the past week. A second DoJo didn't survive more than 12 hours.

Until this incident, our danios have been happily playing near the top of the tank most of the time, and sometimes chasing each other through the caves. So far, it looks like only one danio is behaving strangely. He doesn't appear to be gasping or darting. He's spending most of his time "pacing" back and forth in the same spot near the bottom of the tank behind a cave. We did notice that he seemed to be swimming against the filter intake current for awhile but now he mainly paces around in that one spot near the bottom. But he still shoots to the top for food.

We have noticed that a couple fish we lost did get sucked to the filter intake grate when they weakened. Would the danio be smart enough to know that and say away from grate?

 

[WILDER]

Immediate water change and increase aeration.

Until we know your water stats we are guessing what's going off.

 

[dipsydoodlenoodle]

I dont know if it's possible but he could have "shimmy". I dont know if only livebearers get it however.

 

[luckyd]

Thank you all. I will try to get the water parameters ASAP. We change the water and vacuum the gravel weekly. We did another 30% water change last night and vacuumed. The danio that is acting strange is our smallest one. He did come up again for food last night and hung out with the gang and looked pretty normal for awhile. But this morning he was pacing down by the cave again. I looked up shimmy and I don't think that's it because the fish is swimming back and forth, but just not very far. It's like "pacing" where he swims forward, turns around and swims back over and and over, all within the space of a few inches near the cave. He kind of looks nervous. Could it be he's being bullied?

 

[stubert]

One of my danios was doing something like this, like swimming in the same spot close to the bottom of the tank for a few days in a row, then did it a few weeks later, was a while ago but seems fine was always eating and looked healthy

 

[luckyd]

One of my danios was doing something like this, like swimming in the same spot close to the bottom of the tank for a few days in a row, then did it a few weeks later, was a while ago but seems fine was always eating and looked healthy

Thank you! That's good to know. The fact that it's eating is a good sign I think. Is your danio back to "normal" now?

 

[stubert]

One of my danios was doing something like this, like swimming in the same spot close to the bottom of the tank for a few days in a row, then did it a few weeks later, was a while ago but seems fine was always eating and looked healthy

Thank you! That's good to know. The fact that it's eating is a good sign I think. Is your danio back to "normal" now?

yeh i dont even know which one it was lol all acting...like danios ;P

 

[luckyd]

One of my danios was doing something like this, like swimming in the same spot close to the bottom of the tank for a few days in a row, then did it a few weeks later, was a while ago but seems fine was always eating and looked healthy

Thank you! That's good to know. The fact that it's eating is a good sign I think. Is your danio back to "normal" now?

yeh i dont even know which one it was lol all acting...like danios ;P

I know -- they move so fast it's hard to keep track! Thanks for your help.

 

[stubert]

One of my danios was doing something like this, like swimming in the same spot close to the bottom of the tank for a few days in a row, then did it a few weeks later, was a while ago but seems fine was always eating and looked healthy

Thank you! That's good to know. The fact that it's eating is a good sign I think. Is your danio back to "normal" now?

yeh i dont even know which one it was lol all acting...like danios ;P

I know -- they move so fast it's hard to keep track! Thanks for your help.

haha. Well don't take what ive said as God word still keep an eye on yours but sounds pretty much the same

 

[luckyd]

Thanks! I'll definitely keep an eye on it, and get the water tested to make sure everything's in order.

 

[WILDER]

Have you tested the water yet?

 

[luckyd]

No, it's been a little crazy with work, but I'm planning to go to the LFS tomorrow morning. The danio seems OK so far, although still pacing at the bottom. I definitely need to buy my own kit so I don't have to run to the store everytime there's a potential problem! I'll let you know the results as soon as I get them. Thanks for the follow up.