Tank size and fish compatibility

Question
Hi there,

I'm looking into purchasing some fish as pets for my family. Typically looking for four that can be easily distinguishable (to avoid confusion and fights over who's fish is who's!)and safe in freshwater with a filter.

I have been contemplating green barbs, golden barbs and catfish as I believe these can be kept at room temperature in the mid 60's F.

Is it okay to keep a group like this in the one tank? And is it alright to buy just one or two of each type mentioned above (as in 2 green barb with 2 golden barbs) or must they be bought in larger groups?

Also, if I were to get 4, what size of tank should I be looking at? I don't want to overcrowd but I don't want the tank to look empty!

I did keep fish when I was younger, but in the old fashioned sense. I had a tank, no filter and just two fish sold as goldfish, but apparently suitable for a 19 litre tank (5 gallon) as told by the local pet store, which seems shockingly small now!

Thanks for your time and expertise!

Hope to hear from you soon,

Eilidh

Answer
Sorry for a late response. We've had some power outages due to the earthquakes here.

Barbs need a heater and they do better in an environment with a heater. Barbs need a 20 gallon aquarium. They sell some good brands at Petsmart ranging 70-80 USD that come with the whole lights, filter, and heater.

I would add two more due to them liking schools of 6+. Then I would look at some bottom feeders like a Clown Plecostomus, not a common pleco, and a Dwarf Gourami for finishing off the tank. Both species are easily distinguishable.

- Ash