Cory cat mouth erosion??

Hello - I have a problem with what appears to be whisker abrasion or some sort of bacterial infection with my cory cats; one has been in the tank for about a year, the others are a recent addition (MelinI corys) -- the Melinis were added about a week and a half ago. The older cory is an albino (not sure what kind), and was a survivor of a school of three - all three had their whiskers basically degrade and eventually disappear, but they all seemed fine and ate well. Then two suddenly died about a month ago, after beginning to swim erratically, within a week of each other. I had not been as religious with my water changes as I should have been at that point (I was doing it every two to three weeks ) - after beginning weekly changes, there were no more deaths. Everyone currently is acting healthy, swimming around and eating well, but I just noticed today that their whiskers are looking sort of like they're falling apart... I'll try to post a picture later. None of the other species are affected at all.

Aquarium is a 55 gallon long, kept at around 75 degrees F. Magnum 350 filter and a UV sterilizer. Gravel substrate. No plants (because of plant-eaters in the tank), but lots of hiding places. It's been set up for five years. I change the water once a week, and my hubby cleans the filter once a month (he's afraid I'll break it).

Parameters: pH: 7.6, Ammonia: 0, Nitrite: 0, Nitrate: 40-80 (API test kit), Hardness: 68 (CaCO3 grains per gallon), Phosphate: 1-2.

Stocking: 2 Silver Dollar Tetras
1 Neon Tetra
5 Glowlight Tetras
1 Black Phantom Tetra
1 Albino Cory cat
3 MelinI Cory cats
1 Synodontis catfish
1 Bristlenose pleco
3 BosemanI Rainbowfish
3 Red Irian Rainbowfish

Any suggestions would be very much appreciated - I don't want to lose any more cory cats!! Thank you!!!

 

Are you doing regular gravel vacs?
Normally, when cories are having issues with their barbels, its a substrate issue (cleanliness or too harsh/sharp). Switching to sand substrate may help as well. I know of people who have kept cories on gravel with no issues but I prefer sand as I feel it's more forgiving on their barbels. Plus, cories love sifting through the sand looking for food and is quite fun to watch them bury their little faces into it, eye balls deep, then shoot the sand out through their gills!

 

Can you please place a pic of the gravel?

 

Yep, I vacuum the gravel every time I do a water change. I'll look into sand, though it might be a hard sell to my hubby... he likes the look of the gravel. Here's a picture of the gravel and one of the MelinI corys - I guess the barbell damage is kind of subtle at this point, because it doesn't look so bad in the picture, but you can see it with the naked eye. Plus, I just noticed it, so it's pretty new (I give the fishies a quick exam every day when I feed them). Also, the corys get bottom feeder pellets, if that helps with the dx...

I finally got my browser to play nice with the Fish Lore picture editor! Here's what the gravel looks like (and one of the Melinis):

 

The gravel looks okay to me. It's not overly sharp or anything from what I can see. DoubleDutch ?

 

It isn't sharp but the grainsize might be the problem. Cause food gets out of reach quite easy and decaying stuff (low waterflow) will worsen the waterquality in and just above the substrate.

 

It isn't sharp but the grainsize might be the problem. Cause food gets out of reach quite easy and decaying stuff (low waterflow) will worsen the waterquality in and just above the substrate.

Do you mean low waterflow in the gravel itself or in the tank in general? In addition to the filter and UV Sterilizer stirring up the surface, I have two sets of bubblers in the tank... though I suppose that the water movement might not get into the gravel layer. I take it once-a-week vacuuming won't keep up with the decay rate of any "stuff" in the substrate? Hmmm... might explain why I'm having trouble keeping nitrates down (even with reducing food amounts, it stays at 40-80 ppm). Would you suggest going bigger or smaller with the substrate (assuming I can't convince my hubby to replace it with sand). And would I end up messing up some of my nitrogen eating bacteria if I replace the gravel?

... another thought - would taking out some of the gravel so there was only a thin layer serve the purpose? Thank you to both of you for you replies so far, btw!

 

I meand waterflow in the substrate and just above it. Just trying to share thoughts and experiences. Strange thing is this more often seems to occure in case of a quite thick layer of bigger grained gravel. It's not sharp at all so there must be something else causing bacterial growth causing this I'd say.
If you're not changing to sand try to make a "beach" on which you'll feed. So all the food is eaten.

 

I have found that my cories are sensitive to higher nitrates and more susceptible to barbel infection if I let the nitrates get too high. 40-80 seems a bit high to me for cories, just based on my experiences.

 

Maybe I should do bi-weekly water changes to get the nitrates lower, then.... I'll see about setting up a feeding beach or some sort of platform for the pellets, too. Thank you!

 

I put in a bowl last night to give the fishies time to get used to it. Then I put the feeder pellets in there this morning. At first I thought it wasn't going to work, but then looked over at the fish:



Another benefit is that it looks like the rainbow fish are afraid of the dish (they'd been stealing some of the corys' food before)...

 

I feed my bottom dwellers sinking pellets when I turn out the lights in the evening. Feeding in a darker tank in the evening might lessen the rainbow's chances to steal the food

 

Thank you, good idea!

 

Does this look like the barbels might be healing? I've been keeping the nitrates down to 10-20 (bi-weekly water changes/gravel vacs), feeding them better, and adding a half-dose of Stress Guard every day (per label instructions). The barbels seem to be regenerating, but are white... does this mean they might be healing?