NanoTank

Lucy

Unfortunately, I would take a good guess that your fish are stressed by being in too small of a tank with so many tank mates.

capekate

I agree with Lucy, your GBRs are most likely stressed out and will not show any of their wonderful color in that tank that is about 5g US. Your fish should really be in a larger tank. Best of luck with them...

URFisher35

20 liter tank = ~5 gallons. As Lucy said, your tank is wayy overstocked. A pair of GBR alone should have 20 gallons, the Gouramis should have 10, as well as 20 gallons for the 12 dither fish. The reason you don't have vivid color is because your fish are stressed...

...and just a word of caution Bettas (Siamese Fighting Fish) don't usually work well in community aquariums. They are more of a solitary fish.

URFisher35

Yea...males are very aggressive even to females. they are a solitary fish usually kept by them selves...they are happier that way!

and by way of a bigger tank...i'd definitely look at least 30 gallons (115 liters) for all those fish

Lucy

Bettas are wonderful fish, but yeah, they do much better on their own. IMO in a community tank, they have their guard up since they can be so territorial.
After you get a larger tank for the other fish, the 4g would make a good betta home

agabr123

also once you get a bigger tank i'd look into getting a full school of zebra danios and cardinal tetras (6 of each kind of fish for a full school). but i wouldn't worry about this until you do get the bigger tank and get it cycled

also, you are probably going to run into territory issues with the two dwarf gouramis in the same tank. are you sure that you have a pair? most LFS don't sell females because they aren't as pretty as the male. in anything smaller than a 55 they will probably fight. personally i would return or sell one of them, that would give you a bit more to work with. for the particular fish that you have, i would go with a 29 gallon tank.

good luck!