Corydora fry with a fuzzy like film

[ashnjared88]

Hello. I'm having trouble with a 2 batches of emerald corydora fry I've hatched out. The first batch hatched on the 8th of April and the second batch batched on the 28th of April. The first batch were doing pretty well until I added both batches to a 20 long aquarium. The 1st hatch was in a 10 gallon and the second hatch was in a 2.5 gal both with sponge filters. The 2.5 had high nitrite levels and a high amount of fry so I moved them both over to a 20 long and the 2nd batch of fry are dropping like flys(I've lost over 60 fry since the move) and a few of the smaller fry from my first batch are showing clamped fins. I feed and remove food from the rank 2x per day. 76 degree temp 0 ammonia 0 nitirite and 10 nitrate in tge 20 long. I have 2 small and 1 medium sponge filter in the tank. I have ich x, API erythromycin and jungle fungus clear on hand to treat them but I'm looking for advice. The bodies I remove all have a white film on them and yesterday I found a fry from the 2nd batch with fuzzy white-clearish build up on its tail. Help please!

Edited May 10, 2023 by ashnjared88
Added photo

[ashnjared88]

I was researching and found an older article posted by the co op about how to treat fungus with erythromycin and ich x so hopefully that helps...

[Colu]

With what your describing could be columnaris that's a gram negative bacterial infections that spreads more quickly at  temperatures over 75 and depending on the strain can kill in 24hr to 7days for some of the cold water stains  it can causes fuzzy white patches that look similar to a fungal infection and cause mass mortality  the most effective treatment I have found is a combination of kanaplex and jungal fungus clear fizz tabs containing nitrofurazone following this treatment plan @ashnjared88

[nabokovfan87]

On 5/10/2023 at 2:26 PM, ashnjared88 said:

Is there a chance these are crossbred?

The fry you're showing here is missing it's top fin 😞

As far as what is going on, my recommendation would be to start with the basics....

In your 20L:
1. What are all of the water parameters, including temp?
2.  What is your filtration and is it sufficient for the population boom?
3.  What is the substrate?
4.  What are you feeding, how much, how often, and when it comes to the 20L itself is there mulm for the fry to graze on in excess when need be?

I know you mentioned sponge filters, but what kind?  How much air?  Where are they placed?

On 5/10/2023 at 2:26 PM, ashnjared88 said:

I have ich x, API erythromycin and jungle fungus clear on hand to treat them but I'm looking for advice. The bodies I remove all have a white film on them and yesterday I found a fry from the 2nd batch with fuzzy white-clearish build up on its tail. Help please!

I would recommend using aquarium salt.  1/3 or 1/2 cup per 10G for the fish in question.

You would want to make sure oxygenation is sufficient.  The white film is likely related to some sort of extrernal issue irritating their slime coat.  Paracleanse would be a good idea to follow up with as well for the tank once you get fungus and other issues under control.  For now, salt should be sufficient to help with external issues, osmotic regulation, and to give the fish a little bit of electrolytes to fight this thing off.

On 5/10/2023 at 2:26 PM, ashnjared88 said:

I feed and remove food from the rank 2x per day. 76 degree temp 0 ammonia 0 nitirite and 10 nitrate in tge 20 long. I have 2 small and 1 medium sponge filter in

This covers some of the questions above.  I wanted to reply separately just for the sake of clarity.  I would verify nitrate daily at this point.  I would also recommend verifying PH.  If you only have corydoras in this tank, drop the temperature to the 72 range.

Air should be sufficient and you should have "enough" filtration.  As soon as you're done with meds I would recommend adding in some carbon.  Just place it in a media bag near (or on) the sponge filters.

[ashnjared88]

So I found an old post on aquarium co op on how to treat fungus with ich x and erythromycin. On the 10th I dosed the 20 gallon tank with 10ml ich x(5ml per 10 gallons as per directions) and 2 packets of erythromycin following their directions.  I had an ammonia spike yesterday, the 11th, of .25-.50 reading and did a 50% water change and am using fritz complete to bind up any ammonia that might re occur and I re dosed ich x and erythromycin. I'm thinking the ich x and erythromycin either crashed the already present bacteria colony enough for a spike or the deaths finally built up. Although I'm hesitant to think it crashed the cycle since there has been no nitrite present... Also on the 11th the cory I posted in the picture with the clamped dorsal fin(the fry still had a dorsal fin it was clamped down) passed away and so did a few of the younger fry which is what I think caused the spike of ammonia. I haven't had any deaths or any signs of fry in distress since yesterday. I'm going to re check parameters today and go from there. If there are no other signs of fungus or illness I'm going to re dose the fritz complete if the ammonia is present to bind the ammonia up and to let the bacteria colony increase to meet the bioload as long as there is no off behavior or signs of illness. The fritz complete acts like prime does and binds any ammonia. Are there any other suggestions you might have? I retested the parameters and it was showing .25-.50 ammonia 0 nitrite and 10-20 nitrate with a ph of 7.4. I just read on the fritz FAQ and it states that it doesnt release the ammonia back into the water column that the ammonia continues into the nitrification process which is kind of confusing. My thought when dosing the fritz complete and not changing the water right off the bat is just that of a fish in cycle. I figure as long as I can bind the ammonia to make the fry safe then its giving the bacteria time to catch up to the bioload. Am I off in this thinking in this application do you think, even if the ammonia is made inert? Mind you this is not preferable just the situation I'm stuck in that I wasn't expecting. I'm just hoping to do the right thing and make the best of it. I'm also hoping that by buying time I'm giving the medication time to work.  On a positive note I haven't lost anymore fry and there have been no more signs of the fungus on any of the corys that are swimming around or the ones that have passed. 



@nabokovfan87 This tank is only corydora fry. It's their grow out tank. It has a shallow layer of black sand on the bottom and terra cotta feeding trays and a few pots for hiding in(all from the already seasoned 10 gal tank for the beneficial bacteria). It has 1 sponge filter rated for a 40 gallon tank and 2 small sized sponge filters, I'm not sure what they are rated at. The bigger sponge filter was cycled/seasoned for months and holding the 10 gallon it was in at 0 ammonia 0 nitrites and 10-20 nitrates. I tested that tank right before I combined the 10 and 2.5 gallon. I run the control on the sponge filters on a pretty high setting right after I put in the meds and or any dosing of water conditioner to increase aeration then lower it so the corys can go up and down the glass like they like to. One of the smaller sponge filters had been in my 55 gallon for occasions such as this when I needed the extra cycled filter and the other one wasn't cycled yet. I also have a large pothos vine with a good root system that came from the 10 gallon so I'm assuming it had bb on it in there and various java ferns to help with parameters and oxygenation. 

I'm feeding ground up ocean nutrition fish flakes for all tropical fish and great for herbivores and it has a high protein content too. I dont know how to quatify how much im feeding. enough for them to eat but not enough to be there to decompose. I also have ramshorn snails and a shrimp in there to help consume the left overs if there are any. The tank doesnt have mulm for the fry i just make sure I feed them atleast twice a day. 

I also watched a video from steenfotaquatics stating that salt is bad for corydora since they have scutes and process everything differently than regular fish and the salt can cause permanent liver or kidney damage or death...
The video below states that in treating the fungus the medication can be left in for 5 days then changed out in 25% increments or with carbon.
Thank you, I really appreciate your advice! 
 


https://www.aquariumcoop.com/blogs/aquarium/fish-fungus

[nabokovfan87]

On 5/12/2023 at 10:46 PM, ashnjared88 said:

black sand

what brand?

[ashnjared88]

@nabokovfan87 The fry are emerald corys. I only have had the same group of 5, 3 males and 2 females for just over a year in my 55 gallon. It would be kind of neat if they were crossbred though! From what I've read they will color up around a month and a half or so. They are starting to show signs of the green in certain areas on their bodies already. The flourescent bulbs on this tank dont do them justice.

@nabokovfan87 black diamond blasting sand that has been thoroughly rinsed till the water ran clear. I'm thinking the stress of the tank transition may have made them vulnerable to the infection or fungus...

[nabokovfan87]

On 5/12/2023 at 10:46 PM, ashnjared88 said:

I run the control on the sponge filters on a pretty high setting right after I put in the meds and or any dosing of water conditioner to increase aeration then lower it so the corys can go up and down the glass like they like to.

With a ton of air, the corydoras will do this naturally.  They do so as a sign or breeding or grazing.  It's very normal behavior.  My flow / parameters in the tank are pretty constant but I currently don't do any air stones (running 2 Hobs, 1 spraybar) and the corydoras are quite content to do their up-downs in the circulation.  I just wanted to clarify, that it wasn't the bubbles themselves or the increase/decrease in flow that makes them do that, it's just what they do.

My general advice for anyone with corydoras or cooler species is to pump in as much air as they wish to and the fish will always be content with that.  I use a 150G pond air pump on a 29G tank, 3 drops, the pandas were quite happy with it.  Right now the tank has neo shrimp (also a river species).

 

 

On 5/12/2023 at 10:46 PM, ashnjared88 said:

I had an ammonia spike yesterday, the 11th, of .25-.50 reading and did a 50% water change and am using fritz complete to bind up any ammonia that might re occur and I re dosed ich x and erythromycin. I'm thinking the ich x and erythromycin either crashed the already present bacteria colony enough for a spike or the deaths finally built up. Although I'm hesitant to think it crashed the cycle since there has been no nitrite present... Also on the 11th the cory I posted in the picture with the clamped dorsal fin(the fry still had a dorsal fin it was clamped down) passed away and so did a few of the younger fry which is what I think caused the spike of ammonia. I haven't had any deaths or any signs of fry in distress since yesterday. I'm going to re check parameters today and go from there. If there are no other signs of fungus or illness I'm going to re dose the fritz complete if the ammonia is present to bind the ammonia up and to let the bacteria colony increase to meet the bioload as long as there is no off behavior or signs of illness. The fritz complete acts like prime does and binds any ammonia. Are there any other suggestions you might have? I retested the parameters and it was showing .25-.50 ammonia 0 nitrite and 10-20 nitrate with a ph of 7.4. I just read on the fritz FAQ and it states that it doesnt release the ammonia back into the water column that the ammonia continues into the nitrification process which is kind of confusing.

It might be counter intuitive, but depending on what the load is you may just not have enough biological media in the tank.  Yes sponge has high surface area, but in my experience it isn't the easiest surface for bacteria to grow on.  I had a very similar issue in a very minimally stocked 10G aquarium that was running only sponges.  I also had the exact same issue in a 29G as soon as I removed the small HoB, leaving the 2 sponge filters that had been in the tank for ~4-5 months prior to removal.  As soon as I removed the extremely small amount of biomedia the cycle crashed and I had a cloudy tank for nearly 2 months before I got it under control.  Following that.... The 10G was resolved by adding 3 large lava rocks.  The rocks themselves are about the size of the sponge on the sponge filter and within 24 hours the tank was completely fine with no ammonia or nitrite issues.  My advice would be to add some lava rock, pumice, or ceramic media to the tank in some way.  you can move it near a sponge or try something like this:

https://www.amazon.com/Lees-Triple-Flow-Corner-Filter-Small/dp/B0002APWDS/ref=sr_1_5?keywords=lees+filter&qid=1683957797&sr=8-5

There are surfaces for the bacteria and there are ceramics, but something that has the structure and pores to do that biological support for the tank will give you a little bit better stability in my experience. 

Hopefully you're able to sort out exactly what is causing the instability.  Given the deaths you're experiencing, ignoring water quality issues, I would not rule out some sort of contaminant as well.

Here is the 10G as an example.  It houses a single corydoras with the nano sponge filter and 5 swordtail juveniles at the time of the issue.  Very low plant load and you can see the sponge filter.

[ashnjared88]

Sponge filters aren't usually my main choice for filtration but it is what I use in most of my tanks as a back up just in case. I usually prefer hob but I don't have an extra one to put cycled media in atm. I do however have some ceramic rings and some lava rock I could add in. I'll put in some tonight to see if it helps to remedy the situation. Hopefully I can get this tank balanced and get these cory fry grown and next time have an established tank to put fry into and not need to do a transition mid fry rearing. 

Thanks for all the advice!