Danios Dying One By One. Please Help!

[luckyd]

We started with six danios that we've had at least four months. Four are left, and two of those are showing symptoms. No other fish appear affected so far. Thanks for any advice you can give!

Tank size: 34 gallon
pH: 8.5
ammonia: 0
nitrite: 0
nitrate: 10
kH:?
gH:?
tank temp: 81.2 F (ranges from 80 to 81.5)

Fish Symptoms (include full description including lesion, color, location, fish behavior): A few weeks one of our danios became weak and died very quickly. We chalked it up to a possible injury. A couple of weeks later we noticed another danio acting strangely, swimming back and forth near the bottom of the tank, but still eating. It eventually re-joined the other danios. But a few days after that we noticed a single white bump on the top of its head, which appeared to fall off quickly. But the top of its head remained red looking for several days. Then the danio disappeared, and yesterday we found its body under a decoration.

Meanwhile, in the last couple of days two other danios are showing symptoms. One appears to be weakening and swimming back and forth just above the water jets. On close examination it looks like it has some reddish patches on its skin just behind its fins. It is not eating, and we have now isolated it.

Another danio has whitish looking patches/spots on both sides, and also appears to be weakening. It seems to swim a bit, let the current carry it for a moment, then swim forward a bit again. The spots/patches showed up yesterday but it didn't appear to be weak until today.

Danios swim so fast that it's hard to really get a good look at the lesions. I don't think they look like salt sprinkles but I suppose it could be the irritation from some sort of parasite like ich. But I'm afraid to treat for ich unless I know that's what it really is.

Two other danios so far show no obvious symptoms. Neither do any of the other tank inhabitants.


Volume and Frequency of water changes: 30 to 50% once a week, Red Sea Tank used for freshwater.


Chemical Additives or Media in your tank: De-chlorinators and Stress-zyme with water changes. Filter media include a sponge, white pad, charcoal bag, and ceramic rings in a mesh bag. Charcoal and rings were added within about the last month. I do not add salt because I've read it's bad for catfish. Is this true?


Tank inhabitants: 4 Danios, 2 Platys, 3 Abino Cory, 1 DoJo Loach catfish, 1 golden algae eater. Also a few snails. Yesterday we noticed some tiny dark bug-like things in the decorations near the area where the dead danio was found.


Recent additions to your tank (living or decoration): Added a live plant about a month ago. Most recent additions were two DoJo's. One died within 12 hours, the other is healthy.


Exposure to chemicals: None known other than dechlorinator.

 

[WILDER]

How big are the spots.
Do they look hard, or soft like filled with fluid.
Any redness to the spots.

Any signs of flicking and rubbing, excess mucas, darting, erratic swimming, laboured breathing.

White spot will looks like grain of salt, or the fish has been sprinkled in salt.
If whitespot left untreated the spots will join up to form a patch.

 

[luckyd]

Thanks for your reply, Wilder. There are three danios still alive. I did treat for ich and no more fish have died since. We never really did see the salt sprinkled look, just one or two larger looking white spots on a couple of them. Once we saw a large white spot on a danio's head. About half an hour later the white spot was gone but it still looked like there was a reddish bump. That fish died a few days later. Another danio had one large white spot on each of its sides that later became reddish. So far that fish has survived although the red spots are still there. The red spots are roundish and look like an irritated lesion. I don't see any mucous and it doesn't look hard -- more like it's eaten a bit into the skin.

I never noticed any rubbing or scratching but all affected fish did start to "pace" around in one spot. They also lost their appetite. Even now, they don't seem to be eating much and are kind of listless. But they also don't seem to be getting any worse and if they weren't eating at all, I think they would be dead by now. Only the danios were affected. Does it seem weird that only danios were affected if it was ich?

 

[WILDER]

I think I would add a bacterial med to the tank.
Spots can soon ulcerate the skin away and form a hole.

What's your location.

 

[luckyd]

I'm in the U.S. in Clearwater, Florida.

Do you think the meds would harm any of the other fish in the tank? It's the 3 danios plus 2 Platys, 3 Abino Cory, 1 DoJo Loach catfish, and 1 golden algae eater.

 

[WILDER]

Bacterial med should be fine. It's more the parasite meds with corys, and catifsh.

The med might knock your water stats. If you can isolate and use the med that would be better.

 

[luckyd]

Thanks, I'll try that and let you know how it goes. And thanks for all the help you give newbies like me!!!

 

[WILDER]

Good Luck.
Please let us know how you get on.

 

[luckyd]

Well, here's an update on the danios. I treated the three remaining danios with Jungle Fungus Clear, which also contains antibiotics. Two rallied, have more energy, and are eating nicely. I think the marks on their bodies may be clearing up too.

The other danio didn't fare as well. He never regained his appetite, and we found his poor emaciated body half swallowed by the filter this morning. We also lost our dojo in the past week, although it's a mystery why he died. I'd hate to think it was the original ick treatment -- we did use it half strength but perhaps it still didn't agree with him.

But, all in all, it's probably a miracle we saved any of our original six danios. Thank you for your advice, Wilder. It looks like it's working!