Ideal fish for 20 gallon mixed tank

coloradoreefer94

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I really would like to get a pair of clowns, but also looking at maybe 2-3 more fish from the list below. Anyone with experience with any of these fish I'd love some recommendations on what the best combos would be! I like colorful fish and prefer no/minimal aggression issues.


cardinal fish (banggai)
royal gramma
fire fish
watchman goby
longnose hawkfish
blue spotted jawfish
high fin goby
hector goby
blue devil
azure damsel
flameback angelfish
cryptic wrasse
candy basslet
possum wrasse
diamond goby
bicolor blenny
 
Don't mix Damsels in a 20 gallon. Clowns are Damsels as is the Blue Devil and Azure. On your list the Royal Gramma and Yellow Watchman. The Blue Spotted and the Candy Basslet are the worst choices on the list.
 
I have a 20 gallon with
* 2 clowns
* royal gramma
* yellow watchman goby
* springers damsel

They have all been together for at least a year (first fish added over two years ago, the rest added slowly over time with the last being almost exactly one year ago).

I tried a fire fish but it died from disease (I suspect it arrived with ich and I wasn't doing proper quarantine at first). You may have better luck with them.

I considered a possum wrasse and cardinal but they were not available locally at the time so I got the alternates.

I would rule out any damsel with an aggressive reputation
 
I really would like to get a pair of clowns, but also looking at maybe 2-3 more fish from the list below. Anyone with experience with any of these fish I'd love some recommendations on what the best combos would be! I like colorful fish and prefer no/minimal aggression issues.


cardinal fish (banggai)
royal gramma
fire fish
watchman goby
longnose hawkfish
blue spotted jawfish
high fin goby
hector goby
blue devil
azure damsel
flameback angelfish
cryptic wrasse
candy basslet
possum wrasse
diamond goby
bicolor blenny
Please don't put a Springer Damsel in a 20 with a pair of clowns. You might get lucky for a while, but then you won't.

You could do a Highfin Goby with a clown pair in there. If you do a single clown, or no clown, you open up your options. But a pair of clowns can take over the whole tank and not tolerate any other fish. Clowns can be evil.
 
I would take the damsels, angelfish, hawkfish, candy basslet and possum wrasse off the list, the tank is not big enough if 2 clowns are already there.

The firefish, royal gramma, and any blennies or gobies will want lots of rockwork to be comfortable and be able to hide from the clowns if they need. If the tank is all open arches they won't be happy.

IMO try to keep it to 4 fish total.... fish can sometimes live peacefully for 1-2-3 years, but fish grow and attitudes change and the aggression eventually comes out. I've had this experience a few times.
 
The ones crossed off are going to be problematic in a 20 for a few reasons.

cardinal fish (banggai)
royal gramma
fire fish

watchman goby
longnose hawkfish
blue spotted jawfish

high fin goby
hector goby
blue devil
azure damsel
flameback angelfish

cryptic wrasse
candy basslet
possum wrasse
diamond goby
bicolor blenny

The remaining ones may also need to be removed, I don't remember all of these fishes and their requirements.

A mated pair of clowns is a full house for a 20, imo.
 
I'm in the process of deciding on fish for a 20g. So far I have a springeri damsel because I like a fish for little pests and 20g is too small for a sixline one of my favs. If I decide to add clowns (I have two black ocelaris juveniles) the damsel will come out. I'll only add clowns if i decide to add a nem and they will be the only fish. IMO adding anything with two clowns in a 20g is just asking for trouble once they start spawning.
This 20g is the smallest tank I've ever set up and I'm realizing just how limited the selection of fish that can be combined in a small tank really is if I want a peaceful tank. I leaning toward some interesting inverts and coral vs more fish but can't make up my mind.
 
I had 4 fish in my 20g
two clown fish, a yellow watchman goby and a fire fish. I felt like this was a good stock for my tank, and I never had any issues with these fish.
 
If I only put one single clown in there, are there any fish on that list that are still a no-go?
My opinion is that aside from the glaringly obvious (housing a large predator with small prey, etc) there are no hard rules you must follow. There are others who disagree.
To me, it's all probability and risk management/acceptance. There is no guarantee that any individual fish will get along with any other individual fish - some combinations are more or less likely to work, but "weird" things can happen either way (fish that "shouldn't" get along sometimes will, and those that "should" sometimes will murder one another).
I researched my selections for a long time and decided they were likely enough to work together that it was worth it for me to try them out.
 

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