Otos Wasting Away?

[Knestis]

We started with 15 healthy Otocinclus, whatever they sell as "affinis" around here, probably vittatus? We've got a 75 gal tank, 7ish pH, nitrates max at 40ppm between water changes; no live plants because we've got Metynnis Silver Dollars and they wipe any living flora clean.

Problem is that we've lost several of the Otos some sort of wasting issue. They appear to eat well but lose muscle mass in their bodies. Their bellies are nice and fat but their tails get skinny in a couple of weeks and they expire. We're supplementing incidental algae in the tank (there isn't much, as we don't have any extraordinary lighting/CO2/whatever) with zucchini and spinach leaves, pretty much available for grazing on-demand five days/week. (It's an office tank with nobody here on weekends.)

They all eat enthusiastically. Smaller ones seem to have succumbed earlier, and several still look great, but we lost another two last week.

Any ideas? Thanks in advance...

Kirk in NY State

[Supercorygirl]

Temperature and stress come to mind. Silver dollars can be bullies and generally aren't recommended for smaller tankmates. Temperature when too high can kick start their metabolism into high gear so they are eating but still starving. My two cents anyone hope it helps.

[Knestis]

Temp is very consistent at 76*F. Tank's in an air conditioned room that's below that, so no need for a chiller. I didn't really think to check if the Otos like cooler water. The Metynnis are busy - they keep the tetras reminded that they're down the food chain, just by being bigger and faster - but they aren't nippy. I'll watch tomorrow for evidence that they're intimidated though.

K

[Supercorygirl]

Those 2 discovered due to my own errors, i shudder over how many I lost due to temp too high. The stress I discovered as I had a school of skull creek rainbow juvies in a 15G with otos and couldn't figure out why I lost 2/6 when it was a stable tank, the rainbows were too energetic and stressed them out. I have around 10 in a 75G planted, where the most rambunctious fish in it are Panda corys and they are thriving. The problem is fish stores sell a mix bag of otos, its hard to know what temp needed unless I'd. I keep my tank between 72-76F and works for my bunch. Yours could prefer lower 70's or the only other option could be parasites.

[Knestis]

Thanks for thinking about this. We had a heater thermostat failure last winter and ran the temp up to 90* degrees before we caught it. Did in a nice Bristlenose and two of our Metae corys. Very sad.

K

[racoll]

I would go the other way and suggest that the temperature are too cold for the otos. They generally like it above 80F. Maybe try upping it a bit?

[Supercorygirl]

Again depends on what he has, Racoll. In my mix bag of 10 fairly certain I have quite a few species. I believe mine are vittatus, vestitus, mariae for majority with 1 affinis as has lovely mettalic stripe and 1 I believe to be huaorani based on tail markings, all purchased on 3 separate trips to my fave LFS and all labelled otocinclus. All but the vestitus and huaorani prefer 69-79F according to here. This is just my experience with these little guys

[racoll]

Yes, they are often mixed and imported from various locations, but as far as I am aware the ones in the trade all come from areas with the same environmental conditions, i.e. large rivers and lakes of the warm Amazon lowlands.

[Knestis]

Before...



...and not doing well now. This is the most recent one that's faded dramatically in the past week.



K

[TwoTankAmin]

My 2 cents is you should read the Wasting disease info found here: http://www.inkmkr.com/Fish/FlubendazoleArticle.pdf Fish that are eating but wasting normally means more than stress, imo.

Here is the intro and a later on quote:

This article is first about hydra and its eradication. Secondly, it is about a lot of relief from some of the most hideous afflictions of tropical aquarium fish, including wasting disease, which is often associated with the presence of Hexamita, a protozoan parasite, and velvet disease, a common scourge of captive killifish which is associated with the presence of Oodinium or
Oodinium-like organisms......

The hydra-killing Flubendazole that I used in my office aquarium to eradicate hydra led me to a larger realization. The “wasting” fish in that tank seemed to become cured when I added Flubendazole to the water. Whoa! This was quite a remarkable revelation. My intent was to remove the hydra and any possible nematodes and, to my surprise, the disease I have found to be associated with a particular protozoan species was cured.

The author sells both Flubendazole and Levamisole HCL. http://www.inkmkr.com/Fish/

[CoryfanAad]

Could it be a lack of protein is a possible cause. Noticed my Oto's aren't that great algae-eaters, but love protein.

[Knestis]

Lost the patient in the pic above last night. I hate that.

Some of the school is still busy and eating. The rate of onset of symptoms is quick - like 7-10 days? - and they haven't all gotten sick at once. It SEEMS like a parasitic thing so I'm off to learn more about protozoans and nematodes.

K

[Supercorygirl]

My 2 cents is you should read the Wasting disease info found here: http://www.inkmkr.com/Fish/FlubendazoleArticle.pdf Fish that are eating but wasting normally means more than stress, imo.

Here is the intro and a later on quote:

This article is first about hydra and its eradication. Secondly, it is about a lot of relief from some of the most hideous afflictions of tropical aquarium fish, including wasting disease, which is often associated with the presence of Hexamita, a protozoan parasite, and velvet disease, a common scourge of captive killifish which is associated with the presence of Oodinium or
Oodinium-like organisms......

The hydra-killing Flubendazole that I used in my office aquarium to eradicate hydra led me to a larger realization. The “wasting” fish in that tank seemed to become cured when I added Flubendazole to the water. Whoa! This was quite a remarkable revelation. My intent was to remove the hydra and any possible nematodes and, to my surprise, the disease I have found to be associated with a particular protozoan species was cured.

The author sells both Flubendazole and Levamisole HCL. http://www.inkmkr.com/Fish/

Sorry to hijack thread, but I was curious I had thought wasting disease was a form of tuberculosis?

[TwoTankAmin]

More commonly a parasite. For example:Pseudocapillaria tomentosa.

Adult nematodes in the intestinal tract damage its lining and rob the fish of nutrients, causing a "wasting" effect.......,,, Juvenile fish with nematode infections are often more severely affected than adults, displaying reduced growth, wasting, or more obvious disease signs and mortality............
Summary
Nematodes, or roundworms, have been found in numerous species of fish. Because they are similar to other worm-like parasites of fish, proper diagnosis is important for effective treatment. Working with a fish health specialist will insure proper diagnosis and legal treatment or prevention. Producers of food and game fish have more limited options for the treatment of infected fish than will the producers of ornamental fish because the FDA has elected to use regulatory discretion with regard to use of drugs for ornamental (aquarium) fish.

Small numbers of nematodes may be present in fish without causing significant symptoms. In more severely infected fish, evidence of disease can include emaciation (wasting or significant loss of body mass), nodules or masses present in skin or muscle, stunted growth, abnormal swimming, lethargy, or death.

from http://edis.ifas.ufl.edu/fa091

Or Google "capillaria + fish"

It is more common to find parasites/worms in fish as opposed to TB or Mycobacterium. It is also possible to "cure" infrestations of parasites and worms unlike TB.

[aquariumhobbyist]

Am I the only one to notice the red coloration between the dorsal and the caudal fin?

[Knestis]

That's a good question. It might be a shadow because that's where the musculature/fat has petered out. I'll keep an eye open for it but the remaining Otos were doing well when I left for some work travel on Tuesday.

K

[Knestis]

Update...

For whatever reason, the remaining four of our Otos are looking just fine. My new theory is that I may have gotten a zucchini with some pesticide on it. It was the smaller of the fish that crapped out, making me wonder if the bigger, more robust ones could metabolize something that did in the littler ones could not.

I don't know but I never did anything dramatic (no drugs), the water conditions continue to be pretty much what they've always been, and we didn't change their diet. If anything new develops, I'll post.

Thanks, everyone, for your ideas.

Kirk