Peppered Corydora deaths

[speckles69uk]

Hi everyone,

I wonder if you could help me, I've recently had 2 peppered corydoras die.

I have a 72 litre tank with a Juwel Biofow 6.0 filter and an Air 1000 airpump. I have a selection of ornaments, fake plants and java fern. The substrate is a thoroughly washed play sand. I also have some cuttlefish bone for my snails.

Fish within the tank consists of:-

5 Black neon tetra
5 Male guppy
2 Longnose snails and 1 baby longnose snail
2 Peppered corydora and 1 fry corydora ( This little one was not planned and born in the tank and seemed to have survived - I have let nature take it's course and not interfered, I haven't fed him/her anything different or transferred him to another tank)

Water tests using the API freshwater master test kit are:

pH 7.6
Ammonia 0ppm
Nitrite 0ppm
Nitrate 10-20ppm

Temperature 25oC

I feed them once a day with a high quality flake, algae wafers and catfish pellet food, leaving one day a week without feeding them.

I do approximately a 40% water change weekly.

All fish in the tank appear healthy, they are swimming energetically and feeding. One of the guppys has a larger belly (I'm assuming he's definitely a he, as I've had him for over a month now and no babies have appeared. I've tried them with peas, spinach and veg, as I thought he may be constipated. He's had this large belly since I brought him home, but he swims about happily with his buddies)

There are no noticable marks or unusual behaviour from all the fish other than my peppered corydora recently. 2 of the then 4 corydora were noticably smaller in size to the other two. The last week or so the corys have slowly become more lethargic. The first one that died started spending more time hidden and then on it's side. A few days later (today) the other cory passed away too. The largest of the corydoras still whizzes around the tank and plays in the sand. The remaining one is moving around but not as energetic as the other. I haven't seen the baby fry today, but he seemed ok yesterday when I last saw him. After the first cory died, I did a 100% water change, cleaned the sand and ornaments, but left the filter alone for the bacteria.

Apologies for the long thread. Just trying to work out what is going on with these little ones. Anybody any ideas or suggestions on what's going on and what I need to do?

Any help is much appreciated.

Thank you for taking the time to read.

 

[Delapool]

Nothing really springs to mind unfortunately. Has the temperature been stable?

Edit - how old is the tank and fish?

 

[speckles69uk]

Hi,

Thank you for your reply. The tank has been fully established since December 2013. I fully cycled the tank before adding adding any fish. The peppered corydora were the first I added on the 20th December 2013. I then added the Black Neon tetra and the long nose snails a week apart. The guppies I added in January. Each type of fish were fully acclimated to the water, using the floating bag method. I slowly added tank water to the bag every 15 mins, then discarded the bag water and added the fish to the tank.

I do have a heater, which is set at 25oC. The ambient room temperature may fluctuate from when I have the heating on/off. Unfortunately the weather is not the best here in the UK.

When I carry out a water change, I use tap safe to dechlorinate the water and make sure the temperature of the water is 25oC before adding it to the tank.

The only time I can think of that there could have been a drop in temperature was on Sunday when I did a 100% water change after the cory death. I transferred the fish to a container, which I wrapped in a few towels whilst I gave the tank, ornaments and sand a good clean. But this was after the one death. Two days later the second cory passed away

 

[Delapool]

Everything sounds good to me. I assume that it is a liquid based test not the strips? I wonder if one picked up an internal bacterial infection and just wasn't strong enough (and then passed it on) but I'm guessing so hopefully someone chimes in with some ideas.

 

[speckles69uk]

I use the liquid API freshwater master test kit.

I'm hoping it's something that won't pass on to the other fish. Fingers crossed the remaining two and the baby fry make it

 

[Delapool]

Reckon! It sounded like that as you had the ammonia reading but just in case. Fingers crossed here. Are they doing ok?

 

[speckles69uk]

I've just had a check on them. Nicole ( the largest of the remaining cory) is swimming around fine, playimg in the sand and decorating the tank with eggs. Gary seens to be quiet and hiding at thw moment :-( The little baby fry, Jack, is swimming about, but hard to tell if he's ok as he is quite shy with being the lttle guy. I would like to get them some buddies, as I know they're schooling fish, but I don't want to add any yet, if there is something they can catch.