Stocking Question IM 20 gallon

[r_mcwaters3]

Good evening, morning, afternoon, and beer thirty to everyone.

I have a 20 AIO by Innovative Marine tank that has been up and running for about 5 months. Standard filtration socks on the left of the tank, purigen, and rock rubble on the right. NO skimmer is on the tank. I do weekly 5-10 gallon water changes as a rule of thumb and to keep levels in check.

Fish stocking list currently:

x2 clowns (Sunny and Splash) added 4/25/25, about 1.5 inches in length now
x1 fire fish (Fred) added 5/3/25, about 2.5 inches now
x1 lawnmower blenny (Niblet) added 6/8/25, about 1.75 inches currently

Corals are Zoas

Inverts are a couple of Nassarius snails, about 8-10 blue leg hermits, a strawberry crab (less than .5 inches, and 2 pom pom crabs less than .25 inches.

Now that I painted the best picture I could, for stocking any more fish in the tank, yea or nay? I was thinking of a small sand goby or something similar, but I think 4 fish might be the limit. As far as inverts go, I am going to add some small snails and some more hermit crabs, but really past that, I feel like the inverts list is done as well.

My main question is whether the stock list in my tank to much, about right, or light? It's been a few years, so I figured I would ask the experts.

 

[Rocks reef]

Smaller fish would be a great choice. I'd hold off on adding another for a couple weeks thought to allow the bacteria to colonize to the current bio load since you just added a fish yesterday. Some of the smaller gobies have great color and personalities as well!

 

[r_mcwaters3]

Smaller fish would be a great choice. I'd hold off on adding another for a couple weeks thought to allow the bacteria to colonize to the current bio load since you just added a fish yesterday. Some of the smaller gobies have great color and personalities as well!

absolutely agree on waiting a month or more before adding anything fish-wise but is there a good, longer living, nano fish?

I wouldn't mind something that swims in the water column, like the fire fish does

 

[Rocks reef]

Have you looked at the Orchid Dottyback?

 

[r_mcwaters3]

Have you looked at the Orchid Dottyback?

I did not, purple is nice, that may be a possibility as the last fish

 

[Rocks reef]

They can be quite personable too. I do like the splash of color they add.

 

[r_mcwaters3]

They can be quite personable too. I do like the splash of color they add.

I have always heard he dottybacks are aggressive Has that been your experience?

 

[JumboShrimp]

I have an IM 20 as well. With four fish, you are probably 'finished'... or one more fish from being finished. Lol. Maybe a Possum Wrasse?

 

[r_mcwaters3]

I have an IM 20 as well. With four fish, you are probably 'finished'... or one more fish from being finished. Lol. Maybe a Possum Wrasse?

So I have heard getting a possum wrasse can be finicky to feed, not against it at all, but want to be really careful. Yea im going to look at Rates and Phosphates after a few 6-8 weeks and see if the levels are acceptable with just WC

 

[JumboShrimp]

Agreed. Maybe set up a small, no-frills temporary 10 gallon tank (which you wouldn't necessarily have to completely fill), and get him feeding well; maybe even a small acclimation box to get him feeding in the 20 gallon DT.

 

[JumboShrimp]

(Also I wasn't commenting so much on the bio load, but on aggression. I'm sure you have quite a bit of rock in there, so once you get up to four or five fish in that footprint, the tank mates might not stay so happy.)

 

[r_mcwaters3]

As this merits a picture, here is the tank prior to fish, but the rock hasn't changed, it's a wall in the middle of about 18lbs, so they have a race track they can swim all around the rockwork.

went simple and easy for flow and looks, not as natural looking as I wanted, but if I move to a bigger tank in the future, it will make a cool island

 

[Gumbies R Us]

As this merits a picture, here is the tank prior to fish, but the rock hasn't changed, it's a wall in the middle of about 18lbs, so they have a race track they can swim all around the rockwork.

went simple and easy for flow and looks, not as natural looking as I wanted, but if I move to a bigger tank in the future, it will make a cool island

I love the aquascape!

 

[Rocks reef]

As this merits a picture, here is the tank prior to fish, but the rock hasn't changed, it's a wall in the middle of about 18lbs, so they have a race track they can swim all around the rockwork.

went simple and easy for flow and looks, not as natural looking as I wanted, but if I move to a bigger tank in the future, it will make a cool island

That looks really nice!!