Trying To Nail The Cause

[BryceHockey]

Hello cory lovers. I realize that this would be better suited for the fish emergencies section but it goes a little deeper than that. I have a 46 gallon tank, it's a community tank setup and has been stocked after cycling since last November (so most of the fish have been owned either 1 year or just a little less). I had six Three-lined cories originally, and about six months ago made the horrible dramatic/tramatic switch to sand from gravel. I really thought I would lose fish because of how cloudy it became but all fish survived and are doing great. Since stocking the tank, minus the cories (about to explain that), I have only lost one phantom tetra, and it was of old age (he was moved down to that tank after being in my upstairs tank for another year and a half).

Anyways, about 2 months ago began a very sad and slow loss of my cories. The symptoms have been the same for all of them: red near their fins/private area, puffed eyes, and eroded barbels. I don't have a hospital tank, I considered moving the affected cory to my upstairs tank but the gravel isn't very smooth (though not sharp) and I didn't want to hurt it). That cory slowly got worse and died. A few weeks went by and then a second cory started showing similar symptoms and died, and then another, until I had lost 3. The other 3 seemed to be fine for the past week but now are all showing symptoms. The fourth had almost all of it's back fin gone this afternoon when I got home from work, despite being ok looking yesterday (looked rotted off). I had to euthanize it which really upset me, because I used the near-freezing water method and it seemed to be alive for another 10 seconds, it was calm but I absolutely hate that. I have yet to read of a good method despite tons of searching, besides using a knife and decapitating. I don't have the nerves to do that.

My problem is not necessarily what made the cories die. I have read that they symptoms are common of bacterial infections. However, I'm at a complete loss for the cause of the infection. The tank is always cleaned once a week with a 30-35% water change. I run my fingers in the sand to try and get rid of any buildup, but I try to prevent kicking up too much. Would the water changes and stirring up the substrate be affecting the cories? When I test nitrates they only read at about 5 (ppm?) on the API test kit but it obviously isn't the most accurate reading. And of course, nitrite and ammonia readings are always 0, temperature is at 76-77 Fahrenheit.

Can anyone offer any ideas? I dearly loved watching the cories and want badly to get more, but I'm not about to until I nail down the cause. Any help from experienced cory owners would be greatly appreciated.

 

[BryceHockey]

No ideas? How about some tips then from cory breeders (not looking to breed but obviously if you're successfully breeding cories, they're healthy). Diet has been a big concern of mine for my cories, when I had six I would drop three Hikari sinking wafers to each side of the tank after the light was off. Being that it's a community tank, I do worry that the Gourami and Rams might be stealing the wafers. But I suppose if the cories lived for over 8 months and looked okay, that they were getting enough. Is there a better diet or a way that you ensure your cories get food?

At this point I'm not sure what to do, I would love to re-stock the tank with more three-lined buddies but I'm not about to until I get a better idea of what went wrong (or maybe it was just an unfortunate infection that was out of my control... but I would assume there's something wrong). Any response would be appreciated.

 

[FreedomFighter]

That sounds like some form of bacterial infection to me. Sounds like haemorraging (spelling?) of the fins, but i'm unsure of the other problems.

It certainly doesn't sound like a problem caused by you. Oh and for the record, you don't need to stir up the substrate with your fingers, the cory's will do enough of that themselves.

What do you feed the cory's, and how often? And what are their tankmates?

And for euthanising fish, the best way is using clove oil and a splash of vodka.
get a large glass/jug/jar and fill it with tank water, add in a splash of clove oil. This effectively puts the fish to sleep. You then add in some vodka to seal the deal. leave it for several minutes and the fish should have passed.

 

[BryceHockey]

Cories don't dig very deep, so I actually do believe it can be smart to run your fingers deep into the sand carefully and get trapped air bubbles out.

Does anyone have any advice? Any cory breeders know of anything that I might not be thinking of? Like I said I am anxious to buy more cories but don't want to lose them again. I'm at a loss for what it could be.

 

[Harlequins]

Hmmm not sure what may have caused your cories demise ,although it sounds bacterial.
Perhaps it was the change over from sand to gravel that triggered it off?? cories are prone to bacterial infections through their barbel...

What type of sand are you using?

I use play sand.

My cories love the sand and do root through it alot,weekly i clean the top of sand first then give it a stir to release any debris/air pockets along with the waterchange.

You say you feed them 3 sinking wafers, corys love a varied diet,i feed mine bloodworm,brineshrimp,mini grandules,daphnia,flakes,deshelled peas etc...obviously not all at once though

I hope you try them again soon

 

[BryceHockey]

Thanks for the response Harlequins! Yes I have play sand, it's from ACE Hardware (I'm forgetting the brand but I remember reading it suggested on these forums). It was given a good wash and everything. It could very well have been the change that did it, but the first cory didn't show symptoms until I believe 2-3 months after the change. If the change is what hurt them that is sad, since it was all for the better good of the cories anyways.

I do feel like I'm lacking in the diet for them, but the sinking wafers are one of the few things that the gourami and rams wouldn't mess with completely. I've noticed that most of the healthy cory owners on these forums seem to have tanks that have only top to mid level dwellers and no fish but the cories near the bottom, which would make sense for feeding purposes. Any good tips for getting them food? My cories never seemed to dash for food, they stayed hidden underneath plants and the big log quite a bit. I even tried feeding at night.

I hope I'm able to get a better idea of how to ensure they are properly fed and such. Also, Harlequins, how do you keep your sand so clean? I vac mine once a week with a 30-35% but there's always a lot of debris on the bottom.

 

[Harlequins]

Feeding wise - if you have fish that nab food first Invest in a turkey baster, add flakes/mini granules/bloodworm in a little tank water then suck it up with baster and put it into the tank,it will go straight to the bottom

Mini granules are good has they go straight down anyway

I also clean mine once a week with 30-40% w/c,its helps having 2 good external filters and lots of corys flicking debris around towards the filters
The only build up i find is under the decor that gets lifted weekly,and occasional some in the sand when i stir it around

 

[FreedomFighter]

Well my obvious advice was to get an anti bacterial med..