29 gallon freshwater tank

Question
I currently have 3 paradise fish (1 male 2 female)& 1 redtailed black shark in my 29 gallon tank.
What kind of fish can i add to this?  

Answer
Hello Dutch Gypsy ;-)
As long as your aquarium is established (cycled the beneficial bacteria colonies) there are many species you can try in your aquarium. Platies or swordtails would provide excellent color and activity with the plus of occasional bactches of fry once a month. It's best to keep 1 male to every 2-3 females. The many tetras are also a good choice like Black neons, Black skirts, lemon tetras, Glowlight Tetras, And many others. Paradise fish can be bossy fish so keeping them with fish too large to be eaten but still small and tough to hold their own is best.

Angelfish also come to mind. You should never overcrowd these beauties, but they do like their own kind and do well with Paradise fish. Two might be OK in your aquarium but you shouldn't add much else other than perhaps a few corydoras cats if you'd like.

Rainbowfish would also do well. But stick to smaller species (some do grow large) The australian rainbowfish has a unique shape and color all their own and love to school together.

Of course then there are the many species of barbs available that would be suitable for your setup.
Gold barbs are very beautiful in their coloration and live up to their name. Tiger barbs should also do well but be sure to keep them in schools of at least 6-8 to minimize any aggression towards other fish.
Not to mention Gouramis like the Blue gourami plus the other color varieties. Sometimes the blue coloration of the original "three-spot gourami" causes paradise fish to confuse them with rivals but otherwise there shouldn't be too many problems.

Then there are the Danios...The quick movers who are schoolers always on the go. All species should be fine.

Paradise fish are a truly beautiful species with a facinating history..Accordingly, they were the first tropical fish to be kept in bowls or aquariums!

I really hope this helps!

Best wishes and happy fishkeeping!
Karen~