How many cardinal tetras?

30. I would add more otos and yoyos also.
Plant heavily

I have 11 in my 45 gallon along with 6 Rasbora het, a mated pair of marble veil angels, four otos, 1 SAE, and 9 corys.

The more you buy they better they will school. You could easily add 20-30 to your tank right now. The least I would add would be 10.

I'd buy a few more than you'd like to end up with. I'd get 20, hoping for a stable school of 15 or so. They'll be a fabulous addition to your tank.

I agree that a number somewhere around 20 - 25 is a good starting point. Good luck!

So I picked up seven cardinals at my LFS today and they are gorgeous! They are like little floating jewels! Seeing them in the context of the tank makes me agree with everyone so far... MORE!!! It is going to be SO pretty!!!!

You can certainly keep way more fish in you tank then you have. Just look at how many fish they cram into those feeder fish tanks.

The point is what kind of an effect do you want to have?

It is better for the fish and there is less competition if you keep the number low. The old rule of thumb was 1 inch of fish per gallon of water. I think from an artistic and fish stress point of view this would still be an upper limit.

I have a 52 gal tank and stared with 16 cardinal and now have 14. They look great in the tank.

It really is a matter of preference.

Are these fish a lot less hardy than their neon cousins? It seems like there's some expected loss involved with their purchase.

I think they're both equally hardy, but the cardinal can be harder to acclimitate. Once they've been introduced and settle in, they're quite hardy. Just make sure to drip acclimate them and they should be fine.

On average, I have a harder time trying to introduce neons. They seem to be less healthy than cardinals on average. The vast majority of cardinals are wild-caught.

As such, they can be subject to considerable stress on the way from S. America to your aquairum. If they make the trip well, you should do very well with them. Once established they're actually one of the hardiest aquarium fish. It's not unusual for them to live for many years.

I've purchased groups of 24 with a 100% loss rate in two days. Many other times, I've purchased even larger groups without a single loss after a year. It's HIGHLY dependent on the condition of the fish on arrival. Acclimate them carefully, but don't dwell on it if they don't do well. It's most likely out of your control.

yeah I have a dozen that I bought the night before I saw this thread. Drip-acclimated them for only about 20 min like I would tend to do with any other fish. They look great and seem to be taking well. I might pick up another 8 or 12 too. They look great in that school!


I have only the cardinals and two spawning pair kribensis in the 29g so I think 20-24 fish would fair just fine in that tank. pretty heavily planted w/hyrgo, watersprite, duckweed, java fern, anubias, java moss, ludwigia, and a few others.


Thoughts?

When you purchased your cardinal tetras, did you place them in a quarantine tank or directly into your main aquarium ? This is a very sensitive fish to acclimate to a tank and most of the time they don't show trouble / signs of disease until a few days after introduction. The price range varies but a good group of 20-30 could range from $60.00 to $100.00, a pretty stiff loss should they succumb to infection that could have been prevented with quarantining and dosing with a preventative medication. I speak from experience and others will most likely agree.

I just dripped them, then put them in the tank which had received a water change a day earlier. I suspect that they will be fine. For whatever reason, that tank has faired very well with new fish/plants etc.

Time will tell.



P.S.
I wasn't going to buy another dozen right away. Give it a couple weeks minimum.

The price I think was $10 for four, so I paid about $32 with tax for a dozen.