Something is killing my cories!

[Krysta]

So I’ve been dealing with this for almost a month now. Every time I think I’ve got it figured out or try to help, it goes sideways. I’ve been on other forums and just get things like “don’t let other people feed your fish.” So, not helpful.

Anyway, we have a 55 gal tank, cycled for over a year, nothing live-planted. Our current stock is:
2 peppered cories (used to be 6 before this)
8 white skirt tetra
1 MM platy (another mysteriously died with wounds on him)
2 sunburst platies
4 green lantern platies

Everyone went in together and has done well since the start. No problems at all. We do weekly WC, between 25-50% depending on testing.

About a month ago, my husband and I had to go out of town for a funeral and my in-laws watched our kids and pets. I left instructions to feed the fish once a day, one small pinch of flakes and one algae wafer per day and we tested and changed the water before we left. When we got back, my daughter saw a Cory just lying there listlessly and next to it was this massive cottony/gooey looking ball of what was probably excess waste and food that my in-laws didn’t think to remove. I immediately scooped it out and tested and cleaned the water. Fish perked up fine.

Within a week, I see a Cory with a white growth on its eye. By the next day, this growth fell off leaving an open wound where the eye should’ve been. Again, I cleaned and changed the water, and I added Melafix in hopes of healing it. When I got home from work the next day, it was dead. I monitored things closely for the next week and realized I had a bad ammonia spike.

I did 25%-50% WC every day last week to get it down, adding Prime all the while. I then noticed one day another Cory had the white gooey growths on it, all over its mouth, head, and gills. It was barely breathing and ended up passing as well. I’ve gone through every single day, scooping out any and all leftover food and any gooey fuzzy floaty things.

Today, I saw a Cory stuck to the filter intake. I poked it and it swam away and I thought it was fine. My husband pointed out it was floating upside down. It wasn’t fighting to stay afloat at all. It looked like it had just a soft coat of down on it, all over, and also red streaks all over its body and fins. I saw another Cory with more white growths on its eyes. These two have also since passed.

What the hell is going on? I’m still battling this damn ammonia spike despite my almost obsessive effort. It’s sitting at almost 1.5 and pH seems low at 6-6.5. It also looks like my nitrates are low. Does this mean my in-laws crashed my cycle?

For this fungal outbreak, which is what another forum told me these growths probably are, they just said keep changing water and not to use meds. The ones my husband got (Lifeguard and Fungus Guard) can’t be used on scaleless fish. The tetras seem perfectly fine and while the platies seem to be feeling the ammonia spike, they’re tired looking but still eating normally.

Does anyone have any suggestions? I’ve been wondering about my setup and if it’s equipped to handle this issue. We run a 350B Penguin filter. Haven’t ever changed the filter media. We also have a bubble wall for aeration. The external corner filter leaves the right side of the tank dead so that’s where a lot of extra food and waste ends up. I’ve been looking at internal filters recently.

Is the fungus in the filter? Should I clean it out or just leave it? I’m so tempted just to move the fish and scrub the entire thing down and do a 100% WC but I know that isn’t wise.

Sorry for the long post but I’m super fed up and frustrated at this point. Any help is appreciated.

 

[FreshyFresh]

Welcome to the site. Sorry about your issues!

All the fish you list have been in this tank for a year? No new additions?

That's excellent that you measure your water parameters and do weekly water changes. When you say you've never changed the filter media in your penguin hang-on-back, does that mean you've never swished the pads out in tank water to clean them?

What is the nitrate reading in PPM for your tank?

 

[Krysta]

We’ve had the tank cycled for a year and had goldfish that got too big. So once we rehomed them, the tropical fish went in. That was this past summer so they’ve been in at least 4-5 months now. The platies went first, then the tetras, then the cories. There were a couple days in between to ensure no diseases.

I have swished the media before. I recently did it last week because my biowheels weren’t turning no matter what I did so I thought they may be clogged. If I don’t go with an internal filter I’ve thought about changing the media to ceramic bio balls and mesh bags.

Right now my nitrates are 0, maybe almost 5? Very low regardless to have such high ammonia. I ended up doing a larger WC after I posted this, about 50-65% and added more Prime and StressGuard. One Cory looks much happier and is swimming around but another is still lazing about. I’ve noticed with my peppereds that they turn darker if they aren’t feeling well or there’s ammonia in the water. The listless one is dark but the active one looks normal.

 

[FreshyFresh]

If you are showing ammonia and no nitrates, my thoughts are something has gone wrong with your nitrogen cycle. There should be lots of beneficial bacteria on all the hard surfaces and on the substrate, but depending on the stocking level, this may not be enough. The fact that your bio wheels aren't turning *could* mean it threw the tanks cycle off? Hard to say. I too would continue with water changes using a product like Seachem Prime or the granular form Safe to treat your tap water and temporarily convert ammonia to safer forms. I would do this until I saw no ammonia.

I personally don't care for bio wheel hang-on-backs at all. If you want a much better HOB, go with an AquaClear. An aquaclear 110 would be a good choice for a tank this size. Canisters are a great option too. What ever new filter you choose, you'll want to run it along side your old one for 3-4 weeks.

 

[Krysta]

It looks like the Aquaclear you mentioned is a hang on. Have you ever tried an internal? When we had a smaller 30g we had a hang on but it was positioned toward the middle and the tank was smaller so it worked better for sucking up debris. This Penguin is only able to be on the left side leaving the right side dead where all the gunk goes. I’ve been wondering if an internal filter would help that problem some.

All of my cories are dying from what seems to be the same thing. Are they just at risk because of the ammonia spike and the fungus has moved in? I can’t say it’s an outbreak of any kind as the other fish are fine.

 

[FreshyFresh]

Assuming this is a 48"x12" footprint tank, it's best to have two filters on it. For my 4 footers, I keep an aquaclear at one end and a canister filter at the other. If you don't want a canister, I'd run two hang-on-backs or like you say, put an internal filter at the other end. I've got one or two internal filters in storage. I don't care for the look of them in my current setups, nor do they offer the amount of media I'd care to put in what I've got setup.

Cories can be sensitive to changes in water parameters. I'm not surprised they showed effects first of your stock.

 

[tanker]

What are your Nitrite and Ammonia readings currently. I think the meds may have wipped out your good Bio. Fungus on any fish is a sign of an open wound. Do you have anything sharp in your tank?? Rock, ect?
Maybe--Maybe When your family over fed tank which killed off a few Corys, now the others are more skittish (because fewer). They could have ran into rocks=fungus. When treating killed off Bio==Causing more deaths.
Maybe

 

[Krysta]

I haven’t given any meds except one dose of Melafix to help heal the first Cory that lost an eye to fungus. And no, they don’t have open wounds. The one we found today had the growths on it’s eyes but it was early enough I could still see the eye. And the one last week it was like it was just a blob swallowing it’s face. Unsettling really.

They have a large amount of open space. The only “rock” I have are two false logs which I moved under the filter away from the dead spot so food/waste wouldn’t become trapped in them. The cories hang out in the calmer dead spot. So only way they’d get scratched was in a panic during a water change?

 

[Krysta]

Well. After I did my large WC, within a day the fungus is back. It’s on one of my last cories. I’m down to two of six now and about to lose another.

I don’t know what to do now. I’ve been obsessively netting out any floating particle I’ve seen, making sure the tank is pristine. It’s got to be somewhere in there. Should I pull the filter apart and see what’s going on in there? I’m so tempted to break down the tank and replace gravel and everything. There is NOTHING on the gravel bed and yet it’s still attacking my fish!

I’ve seen some suggestions of salt and methylene blue dips. Would that work to try to save this fish? One guy said not to put MB in the tank because it’ll stain but I’ve got to do something about it since that’s where the source is. My tetras seem fine and there are two platies that like to hang at the top of the water (not gasping just chilling) but the others are normal. One Cory is fine and active but he’s the last one.

Where do I go from here? I’ve seen differing opinions on Melafix and Pimafix. Any suggestions are helpful. And any ideas on how to battle this ammonia spike, save doing 50%+ WC daily?