Problem with a darter

Hi,

I hope I can get a bit of help here.

I am not new to fishkeeping, keep almost 50 tanks, breeding includes some gobies and gudgeons.
I'm new to darters.

I took five orangethroat darters at a local club auction about three weeks ago (well, no one else wanted them).

The fish are juvenile, about 1", kept in a 5.5g, strong aeration (agitated surface), temp 78-80, diet live artemia and frozen bloodworms, substrate river stone, no tankmates, stable biofilter, ph=7.1, kh=3, TDS=200.
Until today, the fish was active and looked happy.


Problem: one of them is "limping", almost falling on its side when it moves now. No other visible symptoms of a disease, so nothing I can try treating for.

I realize that the chances of diagnosis based on this are slim, but perhaps this is a known problem with darters or there is something wrong I'm doing.

Thank you.

Edited by mikev, 25 July 2009 - 02:11 PM.

I had the same problem with them when I brought them home at first. Darters tend to struggle if there are high water temps with low dissolved oxygen. Try increasing the dissolved oxygen via airstone or something. Let me know what happens.

Welcome to the forum Mike and thanks for posting.
Thanks also for the background. As you mentioned a diagnosis is slim but I can suggest one area where I'll bet the fish would appreciate change. I would lower the temperature if at all possible. Many darters can tolerate temps that approach the 80's but can be resentful of long term (even short term) exposure at these temps. It's hard to maintain high oxygen levels at these temps which many darters prefer. If you are an experimental type, perhaps you could carefully dose with hydrogen peroxide and see if indeed your temperature has reduced the ability to hold oxygen. If peroxide makes a difference, oxygen deficiency would be the likely cause of the darters condition. Then again, I could be way off...

Thanks!

Let me try to drop the fishroom temp toward 75F for today and see if this improves the situation any. I cannot do this permanently, unfortunately, or go lower (young fry in the room).

if it helps, it will at least confirm that I need to work in this direction.

aeration can be increased, but it is quite a lot already. H2O2 I'm afraid of.
I don't have any way to measure oxygen, but I know that tanks similar to this in the same room with hillstream loaches (very O2-sensitive, but from warmer environment) show no trouble signs.

I really don't want to lose this one... it is the only female in the group.

No chance it can be due to a fight between them? The only time I've seen similar limping in any fish was after serious territorial fights between loaches.. fatal internal damage or stress.

The gill movement rate of the affected fish is not erratic or elevated, same as others.

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PS. Thank you for the welcome to the forum.

Edited by mikev, 25 July 2009 - 04:34 PM.

I thought the same thing. I thought it had just been in a fight with one of my other fish, so I took them out to see. That darter ended up dying and then 1 to 2 per day after that until I increased the dissolved oxygen. In my case it looked like their tails were being chewed off and the flesh near it was turning lighter. After increasing the dissolved oxygen levels though, the fish in bad condition recovered, and I haven't lost any since then. Hopefully there's some encouragement that she might make it. Good luck!

Lowering water level had a positive effect; she seems/moves normal now and chased artemia like the rest.
(I started dropping temp also, but the improvement happened before the temp changed...they will have a cool evening anyway.)
Thank you; this was good...hopefully would hold too...

I hope you don't mind a few more questions; I meant to join NANFA and ask anyway...but it is always the emergencies that make things happen.

1> Current tank: a 10 sec clip.
Is the aeration sufficient in your opinion?
What would make them more comfortable? Large Stones? Driftwood? PVC's? Java Moss? Java Fern?
(they don't seem to want hiding places so I did not rush with this...and it is easier to quarantine with no extras in the tank.)

2> There are 3 more darters here from the same source; a pair of rainbows and a redline male (the matching female unfortunately lasted only two days...came in with a fin infection...the previous owner gave up on fishkeeping altogether and seemingly did not take good care of them at the end.). Is it safe to put them all together? I'm quarantining them separately for now, but except for the today's problem all looked good...I'll give them additional couple of weeks to make sure.
The other three are adults, 2".

3> If everything goes smoothly, my plan was to get a mate for the redline, possibly a couple more (within the current species), and some matching dither. Ideally small shiners or dace... something that stays around 1"-1.5" and is not an overly aggressive eater. Would you have any recommendations? (Any dither would require a larger tank, naturally.) The appearance does not matter. A common native species would be best. I'm not doing this now, I want to wait until I'm sure I can keep them through Aug/Sep, but I may as well research the dither meanwhile.

Thank you.

1. In my opinion, addition of diffuser/airstone on the hydro sponge would be beneficial (increased O2 and flow). E. spectabile would be found near or under rocks in the wild so I believe cover could only help.

2. I believe the combination you discussed should be fine as long as you have adequate room and cover for them.

3. A native minnow does fit the bill aside from your request for a dither that is not an overly aggressive feeder. Most minnows take any food they can fit in their mouth with gusto but not usually with such enthusiasm to injure darters. Much of this is personal preference but it's hard to wrong with Phoxinus and Lythrurus genus minnows. Both mentioned minnows will usually eat most of the food before darters get to eat, so you will need to accommodate for that when feeding.

Thank you very much; I'll follow your suggestions.

(I guess no native dither for them...it is having to feed darters through a straw every day that I wanted to avoid...)

The fish surprisingly looks fine; I'll make sure to watch them carefully and keep the water level low.

Thank you very much; I'll follow your suggestions.

(I guess no native dither for them...it is having to feed darters through a straw every day that I wanted to avoid...)

You don't necessarily have to go to that extreme. I feed flake food or pellets to my minnows in one corner of the the tank first and while they are feeding drop frozen bloodworms/shrimp etc... into the opposite corner for my darters. This works pretty well, although I have had a couple "smart" minnows that figured out the scheme. At feeding time they go to the darter's corner for the good stuff, but the darters still get plenty.

This would be ok.

In a tank where I have bottomfeeders and White Clouds, I simply feed flakes first and bloodworms ten minutes later, WCMM's mostly ignore the bloodworms. This works with rasboras too. Not danios or rainbows.

Actually, what would be the native minnow most similar to white cloud? This wold be the dither to try....

To better understand the tank requirements, just look at where the orangethroat is found in the wild - small to medium sized creeks with plenty of riffles.

This means cool moving water and lots of O2. They really prefer temps in the 60's, though low 70's seem to work for mine. I double the amount of power filtration normally used on the tank, and add an air stick. Mortality has been very low.