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How many corydoras to keep?
Posted: Fri Jun 20, 2025 9:18 am
by onyxim
I've got a 20 gallon tank with sand substrate and a sponge filter. Wanna add some Corydoras but not sure how many to start with. Heard they like groups, but don't wanna overcrowd. What's the sweet spot?
Re: How many corydoras to keep?
Posted: Fri Jun 20, 2025 9:31 am
by haply
For a 20 gallon, I'd recommend starting with 6 Corydoras. They're social and do better in groups. Make sure your tank is cycled and has plenty of hiding spots. Sand is perfect for them since they like to sift.
Re: How many corydoras to keep?
Posted: Fri Jun 20, 2025 10:20 am
by frosta
I agree with haply. Six is a good number. They'll be happier and more active in a group. Just keep an eye on your water params, especially nitrates, since they can be sensitive.
Re: How many corydoras to keep?
Posted: Fri Jun 20, 2025 10:46 am
by onyxim
haply wrote: ↑Fri Jun 20, 2025 9:31 am
For a 20 gallon, I'd recommend starting with 6 Corydoras. They're social and do better in groups. Make sure your tank is cycled and has plenty of hiding spots. Sand is perfect for them since they like to sift.
Thanks! I'll start with six then. Got some driftwood and plants in there too, so they should feel at home.
Re: How many corydoras to keep?
Posted: Fri Jun 20, 2025 11:11 am
by haply
Sounds like a great setup. Just remember to acclimate them slowly. Corydoras can be a bit sensitive to sudden changes. What other fish are in the tank?
Re: How many corydoras to keep?
Posted: Fri Jun 20, 2025 11:19 am
by frosta
Yeah, slow acclimation is key. I've lost a few Corydoras in the past by rushing it. Now I always drip acclimate for at least an hour. What's your water temp?
Re: How many corydoras to keep?
Posted: Fri Jun 20, 2025 11:42 am
by onyxim
It's at 76°F right now. Got a couple of neon tetras and a betta in there too. The betta's pretty chill, so I'm not too worried about aggression.
Re: How many corydoras to keep?
Posted: Fri Jun 20, 2025 12:25 pm
by haply
onyxim wrote: ↑Fri Jun 20, 2025 11:42 am
It's at 76°F right now. Got a couple of neon tetras and a betta in there too. The betta's pretty chill, so I'm not too worried about aggression.
That temp is perfect for Corydoras. Just watch the betta, even if it's chill. Sometimes they can get territorial with bottom dwellers.
Re: How many corydoras to keep?
Posted: Fri Jun 20, 2025 12:48 pm
by frosta
I've had mixed results with bettas and Corydoras. Some bettas ignore them, others chase. Maybe add the Corydoras first and see how the betta reacts before adding more.
Re: How many corydoras to keep?
Posted: Fri Jun 20, 2025 1:09 pm
by haply
Good point, frosta. It's always better to err on the side of caution. How often do you do water changes, onyxim?