Mari

Hi
I started my 20 gallon tank just about a month ago with 2 cardinal tetras, Billy and Zeze, and they are at 80 degrees F. At first they were a little stressed out and would not eat but now they are extremely happy (it seems), eating flakes, frozen bloodworms, and freeze-dried brine shrimp (only feed them twice a day and one type of food per meal). I don't have any real plants, just plastic ones. I do weekly 20% water changes (use tap water and conditioner to get rid of chlorine) and check pH, ammonia, nitrate, and nitrite levels also weekly. I love my little fishies but now would like to get more fishies... maybe even a african dwarf frog or two. I was reading that the cardinals need to school so I was thinking of getting 3 or 4 more cardinals or other little tropical community fish that will school with Billy and Zeze. I was also told to get an algae eater. Being new to all this, I have a million questions!! First, how many hours a day should my fishies have the light on? I usually turn it on at night (which I am guessing is not good) and leave it on from 9pm to 1am. And now that I am getting new fishies, would you provide me with some info on other fish that will school or be happy with my cardinals? I know that 20 gallon is not that big so I need them to be kind on the small side. I am also getting two frogs so I need to take that into consideration. Also, should I get an algae eater? I haven't had any algae problems yet, however my tank has only been up and running for 6 weeks or so (only about 4 weeks with fish in it)... and who know what the future awaits. Please please if you have any info that you think I could find useful, reply to my post. I would truly appreciate it since I just want to make my fishies as happy as possible.

Luniyn

Your tank would be great to add 4 or so more Cardinals to. They will be very happy with more friends to play with and with your tank you have plenty of room (they only get to be 1.5" as adults normally so with 6 in your tank you would only be taking up 9" of space leaving your another 11" to play with). As to an algae eater, if you don't really have algae then it would only be because you like the look of them. Please don't get a common Plecostomus (aka "Pleco") because they can get to be way to big for your tank. Though you could get something like a bristlenose which only gets to be 5". A good algae eater for your tank would be an Otocinclus catfish (aka "Oto") as they get to be max 2", so 2 or 3 (they like to be kept in groups so 2 is a minimum really) would be nice in the tank. Just remember to feed them algae wafers or veggies since they won't have algae to feed on. Another option, though they don't eat algae, would be a Corydoras Catfish. They are bottom dwellers and are quite fun to watch play in the tank. They will eat food that drops to the bottom and keep it clean that way, but again supplement their diet with some sinking pellets (shrimp pellets are my Cory's favorite food). Most of them get to only be 2"-2.5" max so 2 or 3 (again 2 min) would be great for your tank.

As to the lighting, they need to have a day night cycle like you do. Since you don't have any live plants, you don't need to light the tank at all provided there is some ambient room lighting from either windows (not direct sunlight or you will have an algae problem soon) or just room lights that are left on during the day. But at night they need the dark just like we do so they can get some rest. There are some LED lights that create a light moonlight effect that you can get if you want to be able to observe them a bit, but best bet is when its dark outside, it should be dark in their tank as well.

Radcliffe

I have a combination of 6 cardinal tetras, 2 dwarf frogs and 2 ottos and they have made a very happy non aggressive tank together. They have been together now for a few months with no problems and I would recommend the combination highly! I have them in a ten gallon, so it is a bit overstocked. I do frequent water changes, and if I had a 20 gallon I would happily use the same combination!

Here is a pic of my tank:

Mari

Thanks so much! Such great info... Actually I got 6 cardinal tetras now... they look happy which in turns makes me happy. Also I have now sort of decided to get a betta... how big can they get? i was thinking of getting the betta and maybe a cory or oto to eat the food that my cardinals don't eat... that way it would be a little less messy. what you guys think?

Radcliffe

I am not sure that a Betta with cardinals is a good idea- the cardinals would want to nip at the fins of the betta.

Corys eat food off the bottom of the tank, ottos eat the algae, and both would get on with Cardinals.

--R

Radcliffe

Hmm, reading the other thread, it seems someone has had good luck with cardinals and a betta together. :-)

--R

vin

As long as the group of cardinals is around 5-6 they should be fine with the betta....As for the Otos, they don't eat the left over food like corys do....Whichever you choose try to get more than 1....Ideally you'd want 3 of either you choose. This will help them to feel less stressed. Either one will be fine with Cardinals and Bettas.

Radcliffe

Oooh really? It would be tempting to get a betta to have with cardinals- such a pretty tank that would be!

--R

vin

The reason tetras get nippy is when they feel outnumbered. If in the proper sized school (5 or more) they feel safer...Safety in numbers I guess......And of course as long as the tank is large enough to keep them happy...If they feel cramped that could cause problems as well....

Mari

Well my betta is doing great with my cardinals (6 of them). Plus 2 corys, they are all getting along well I think.
Thanks for all the great advice, and my fishtank looks really nice!