Lone cory cat has white coating

Just setting up a 20-gallon long, heavily planted tank (details at the bottom of the post).

Lightly loaded, and all but one of the 5 small fish seem to be doing just fine. Just one cory cat, of a pair, has a white, slightly spotty coating on his front half, more or less, that improves, then gets worse again. at times, it seems to be shedding a little bit of the coating in small areas. The coating is often hardly noticeable if light hits it from a steep angle, but it looks really bright white if light hits it at a glancing angle. The fish eats OK, but seems a little jumpy, and does scrape against things, similar to what a fish might do with a disease or water quality issue. This fish had a damaged dorsal spine, and a little fin rot, which seems healed, and the problem arose about the time the rot healed.

SEE PHOTOS

I am using API Melafix, but this is just a healing aid, not a cure for anything, it does seem to be helping after 2 days, in the sense that the cory seems less jumpy, and the coating looks a LITTLE better, but that has happened before.

My question is; Does this seem to be fungal or bacterial?

What medication is recommended?

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Doing a 25% water change, once a week, using de-chlor hard tap water, to keep GH up.

2 large sponge filters and a separate ceramic air diffuser, all on 2 Tetra 20-50 gallon air pumps. (plan to add another power filter after the sponges are well-cycled & fish load is increased.

Temp is held near 78F by a heater.

Setting up the clean-up crew and cycling, so at the moment only stocked with

LOTS of live plants in eco-complete black substrate.

A colony of several hundred Malaysian trumpet snails

1 large rabbit snail

1 very large Nerite snail

2 rainbow sharks

1 small/medium pleco.

2 cory cats.

Feeding Tetra Pro Pleco Wafers, and Omega One Super Carnivore (frozen blood worms, brine & mysis shrimp) .

Hmm.. I'm still rather new to the hobby and so far haven't had to treat any illnesses but I like to read a lot.

From what I've learned, it almost sounds like a bacterial infection (think fin rot is also bacterial). Almost sounds like the bacteria from his fin rot delved into the skin on his front half. Which could make sense, since bacterial infections commonly follow fin/tail rot issues or open sores/abrasions if I remember right.

But it also sounds a lot like ich, especially if he keeps rubbing on things and he is extra twitchy/jumpy.

Hard to tell from 2 of the pics, but in the 1st pic are those spots raised bumps, or open sores? The answer could point you in the right direction.

Also, is he showing any other symptoms, like rapid breathing?

Atm, if we assume his symptoms are a white film (following the fin rot healing up) with open sores or raised bumps, he's rubbing on stuff, is extra jumpy.. I'd say it is either ich (parasitic) or bacterial infection.

Hope this helps give you a couple directions to research, between parasitic ich and bacterial infection, as the provided info. will probably correlate more with what you're experiencing in 1 direction or the other.

This article lightly touches on both Ich and bacterial infections, be worth checking out for starting research reference.

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Best of luck - hope your cory gets better!

hi, thanks for the ideas.

The white spots are just discolorations, not raised or open sores.

No issues like rapid breathing, just seems a little jumpy & does rub against things.

Sometimes a few tiny, ich-like white grains appear, stuck on his sides, but they disappear soon - fall off I guess - so I just assumed they aren't ich.

From what I've read, fungal infections also frequently follow fin-rot or other issues, so I didn't see anything to help on that score.

OK, I'll check into your article & thanks again....

How long has the tank been cycling and what are your ammonia/nitrite/nitrate readings?

Hi Adora,

The tank has been cycling for a couple of weeks. I have an API "master" freshwater test kit, an API GH/KH test kit, AND a hardness meter, but haven't used them yet because of the light fish load, and the fact that the other 4 fish, including another cory, all appear to be perfectly fine.

I had thought that the injury to the cory (perpetrated at the store - the employee was a brute with the net) triggered the problems with the one problem fish, but I think you are right - time to use those test kits.

I'll get back to you tomorrow with the results.

I might add that I have a Hygger 48W full-spectrum LED light, programmed with a good day/night cycle. This should be a bright light for this tank, plants doing fine, and it was the biggest Hygger that would fit on the tank - so I think that eliminates lighting issues as a source of stress, as it's not 24/7 illumination.

Look forward to your further thoughts & Thanks!

Depending on the size of the rainbow sharks (and I foresee problems with having two of those in a twenty gallon, they are famously territorial) and the pleco, I wouldn't really call it a light bioload...

I'm going through a mini cycle right now with a 15.5 gallon that only has four adult guppies, a few fry, and shrimp, heavily planted, but nitrites are still getting high enough that it requires a 75% daily change to keep on top of it, and I'm feeding very lightly, with fish that have no where near the bioload of a pleco or rainbow shark.

Always best to keep on top of testing when you're cycling, but especially if you've decided to do a fish in cycle.

I'm no expert on disease, nor cycling for that matter, I hope @Colin_T sees this and can weigh in after seeing the photos, but it looks to me as though the cory is producing a lot of excess slime coat in an attempt to protect himself, perhaps from water quality issues. He might be showing the affects more than the others because he was already in a weakened state, but you can't assume that the other fish appearing to be fine means the water can't be the problem, especially in such a new set up.

While we wait for your test results from your water, you also have a few other problems with this tank. Are you planning to upgrade soon? 20 gallons is not big enough for a single rainbow shark, nevermind 2. Rainbow sharks can be peaceful....but also are known to be territorial, and could potentially be picking on the cory. Even if you don't see this during the day, I found my RBS to be active at night. so it could be happening in the dark.

Pleco's also have a notoriously high bioload. You don't mention what type of Pleco you have but "small/medium" leads be to think it might be a common, which will outgrow a 20 gallon very fast.

AdoraBelle Dearheart said:

Depending on the size of the rainbow sharks (and I foresee problems with having two of those in a twenty gallon, they are famously territorial) and the pleco, I wouldn't really call it a light bioload...

I'm going through a mini cycle right now with a 15.5 gallon that only has four adult guppies, a few fry, and shrimp, heavily planted, but nitrites are still getting high enough that it requires a 75% daily change to keep on top of it, and I'm feeding very lightly, with fish that have no where near the bioload of a pleco or rainbow shark.

Always best to keep on top of testing when you're cycling, but especially if you've decided to do a fish in cycle.

I'm no expert on disease, nor cycling for that matter, I hope @Colin_T sees this and can weigh in after seeing the photos, but it looks to me as though the cory is producing a lot of excess slime coat in an attempt to protect himself, perhaps from water quality issues. He might be showing the affects more than the others because he was already in a weakened state, but you can't assume that the other fish appearing to be fine means the water can't be the problem, especially in such a new set up.

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Adora,

The sharks are small, only 2 inches or a little more, and I do plan to give one away soon. In the tank at the store, and for the first several days /week in my tank, they got along fine, stuck together like glue. Then the slightly bigger one began to bully the other.

The pleco is maybe 3-4 inches and growing rapidly NO visible issues.

I have not seen any bullying of the cory at all....

AdoraBelle Dearheart said:

Depending on the size of the rainbow sharks (and I foresee problems with having two of those in a twenty gallon, they are famously territorial) and the pleco, I wouldn't really call it a light bioload...

I'm going through a mini cycle right now with a 15.5 gallon that only has four adult guppies, a few fry, and shrimp, heavily planted, but nitrites are still getting high enough that it requires a 75% daily change to keep on top of it, and I'm feeding very lightly, with fish that have no where near the bioload of a pleco or rainbow shark.

Always best to keep on top of testing when you're cycling, but especially if you've decided to do a fish in cycle.

I'm no expert on disease, nor cycling for that matter, I hope @Colin_T sees this and can weigh in after seeing the photos, but it looks to me as though the cory is producing a lot of excess slime coat in an attempt to protect himself, perhaps from water quality issues. He might be showing the affects more than the others because he was already in a weakened state, but you can't assume that the other fish appearing to be fine means the water can't be the problem, especially in such a new set up.

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Adora,

Good thought there - that's a good description of it - like excess slime.....

squidneh said:

While we wait for your test results from your water, you also have a few other problems with this tank. Are you planning to upgrade soon? 20 gallons is not big enough for a single rainbow shark, nevermind 2. Rainbow sharks can be peaceful....but also are known to be territorial, and could potentially be picking on the cory. Even if you don't see this during the day, I found my RBS to be active at night. so it could be happening in the dark.

Pleco's also have a notoriously high bioload. You don't mention what type of Pleco you have but "small/medium" leads be to think it might be a common, which will outgrow a 20 gallon very fast.

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Thanks for those tips. I do believe the pleco is just a common type, and it IS growing fast, as you conjectured.....

OK, here's the test results:

Using API Master Fresh Water Test Kit, and API GH/KH Test Kit.

Ph: ~ 7.8 ( off scale low-range, & 7.8 high range)

Ammonia: Barely detectable, SLIGHT green tinge to the yellow. Between 0 ppm and 0.25 ppm, but a lot closer to 0 ppm.

Nitrite: 0.0 ppm

Nitrate: 0.0 ppm

GH: 3 drops to change color of test solution, giving ~ 53.7 ppm

KH: 2 drops to change test solution color, giving ~35.8 ppm

I find the high Ph and low hardness a bit puzzling. The tap water I have is notoriously hard...

I do have a LOT of snails in the tank (Malaysian Trumpet, Nerite, Rabbit) Is there any chance they could be pulling the GH/KH down, making shell?

Doesn't sound like it's close to being cycled, you've only changed 25% of the water once a week, and the tank has been set up for a couple of weeks, is that right? Sorry, did re-scan the thread, but having trouble keeping track of all the tank details.

When did you last do a water change on this tank?

AdoraBelle Dearheart said:

Doesn't sound like it's close to being cycled, you've only changed 25% of the water once a week, and the tank has been set up for a couple of weeks, is that right? Sorry, did re-scan the thread, but having trouble keeping track of all the tank details.

When did you last do a water change on this tank?

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A couple of weeks with fish in it. It's been more like a 1-2 months since I first started the tank, but most of that time it only had snails and plants, with filters running. I figured I might get the tank at least partly cycled that way before putting any fish in it.

It was a bit more than a 25% change; 20 gal tank, minus rocks, substrate, a bit more than 5 gal water removed.

Last Saturday, did the 25% change, via a gravel vac, so the substrate was cleaned simultaneously. I am treating the tank with API Melafix, due to the ailing cory, which seems to be helping. At least the fish is improving for some reason. The Melafix instructions say to do a 1-week course of treatment, then do a water change.

It's excess mucous caused by something in the water irritating the fish or an external protozoan infection (Costia, Chilodonella, Trichodina). If it comes and goes then it's most like something in the water.

Does it get better after a water change?

Try doing a 75% water change and gravel cleaning the substrate every day for 2 weeks. See if it improves. If it does, then it's a water quality issue.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Colin_T said:

It's excess mucous caused by something in the water irritating the fish or an external protozoan infection (Costia, Chilodonella, Trichodina). If it comes and goes then it's most like something in the water.

Does it get better after a water change?

Try doing a 75% water change and gravel cleaning the substrate every day for 2 weeks. See if it improves. If it does, then it's a water quality issue.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

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hey, thanks for the info!

Yes, the condition does seem to improve after a water change.

Improvement is noted w/use of Melafix as well.

Always use Seachem Prime dechlorinator, 3 drops/gal to be double sure dechlor is total.

I do plan to add a UV sterilizer as soon as it arrives in the mail.

A uv steriliser is unlikely to make much difference, especially if it's a water quality issue.