Corydoras Dying Off (SOS!)

[Caravan]

Hey, everyone!

I somewhat recently started my first freshwater tank, and I did my research and due diligence, at least as far as I know. The tank was cycled, and we started slowly adding fish to allow the system to balance itself.

We started with:
Initial load - 4 Albino Corys - 1 died pretty early after purchase and another died this past weekend.
Two weeks later - 1 Male Betta - from what we observe, he's fairly timid and non-aggressive
One week later - 5 Emerald Green Corys - 1 was found dead this past weekend and another looks unwell.


As of Saturday, these are the stats:

20g Long Tank
Aquaclear 30
Lightly planted
Plenty of hiding spots
Light on a 12 hour timer
Ammonia: Near 0ppm
Nitrite: Near 0ppm
Nitrate: Around 20ppm
Temperature: Around 78F until Saturday, Lowered slightly based on information found on the internet
Feeding: 1 Shrimp pellet per cory, twice daily. 3 Floating betta food things, twice daily.
Water Changes: 4 gallons, bi-weekly (Using water treatment to remove chlorine, etc)

I'd really rather not lose all of my corys, but I'm not sure what I can change to make them stop keeling over. I don't think the betta is a factor in their issues. I mostly see him run away from them, but he did nip a small amount upon first being added to the tank.

Any help anyone has to offer would be greatly appreciated. I've done everything I can think to do from a beginner's standpoint.

Thanks!

 

[KingKoopa512]

Hey, everyone!

I somewhat recently started my first freshwater tank, and I did my research and due diligence, at least as far as I know. The tank was cycled, and we started slowly adding fish to allow the system to balance itself.

We started with:
Initial load - 4 Albino Corys - 1 died pretty early after purchase and another died this past weekend.
Two weeks later - 1 Male Betta - from what we observe, he's fairly timid and non-aggressive
One week later - 5 Emerald Green Corys - 1 was found dead this past weekend and another looks unwell.


As of Saturday, these are the stats:

20g Long Tank
Aquaclear 30
Lightly planted
Plenty of hiding spots
Light on a 12 hour timer
Ammonia: Near 0ppm
Nitrite: Near 0ppm
Nitrate: Around 20ppm
Temperature: Around 78F until Saturday, Lowered slightly based on information found on the internet
Feeding: 1 Shrimp pellet per cory, twice daily. 3 Floating betta food things, twice daily.
Water Changes: 4 gallons, bi-weekly (Using water treatment to remove chlorine, etc)

I'd really rather not lose all of my corys, but I'm not sure what I can change to make them stop keeling over. I don't think the betta is a factor in their issues. I mostly see him run away from them, but he did nip a small amount upon first being added to the tank.

Any help anyone has to offer would be greatly appreciated. I've done everything I can think to do from a beginner's standpoint.

Thanks!

Possibly could be the Betta. your water parameters look good . Hmmm.......

 

[OnTheFly]

No salt or Meds added to the tank right? They aren't fond of either in my experience. Are you confident in your fish source? My list is getting shorter every week around here.

 

[TeenyFish]

I KNEW I READ THIS BEFORE!

I replied to you on fishlore [emoji23]

 

[The camaro show]

Please say you do not go to petco or petsmart

 

[Pamiam]

This is what I do with my cories...my 2 cents worth.

I have had coryies for 10 years, mine are in community tank that has a betta...all get along fine. My cories mate all the time, so I know they are happy.

I feed my cories flake food, frozen blood worms, frozen brine shrimp with or without spirulina. They also get shrimp pellets and algae waffers. They get flake food in morning and the rest at night.

I have a large tank with many species, hence the variety of foods...but the cories eat everything I put in there.