What's the smallest tank you've ever setup?

saltwaterfish.com · Aug 10, 2026

I personally have set up a couple different Pico tanks in my experience with keeping aquariums. The smallest being a 1 gallon all in one set up that mainly had Zoanthids, a few mushrooms, and a single sexy shrimp. I upgraded it to a 3 gallon after a couple of years, and then a 5 gallon which it currently sits at with a white cap goby, and a green banded goby. I've seen people do setups as small as a 1/4 gallon but this was mainly as a temporary display, and it had me curious. What is the smallest setup you have ever done, how long did you have it setup for, and attach pictures if you have any please!

JumboShrimp · Aug 11, 2026

The smallest I set up were these two (2) slant-nose 7 gallon all-in-ones. Basically run with filter floss.

UncommonSense · Aug 11, 2026

The first tank I ever built, to wrap my head around the glass cutting, and assembly process… 6”x2”x2”, 8oz fluid capacity!

Then, the first semi-practical tank I ever built, 4G capacity rimless prism, with a monolithic glass AIO divider… AKA The Ugly Duckling:

This tank is still up and running at my LFS to this day!

saltwaterfish.com · Aug 11, 2026

JumboShrimp said:
The smallest I set up were these two (2) slant-nose 7 gallon all-in-ones. Basically run with filter floss.

Beautiful tanks, that's an amazing elephant ear mushroom you've got in there, does it host your clownfish?

saltwaterfish.com · Aug 11, 2026

UncommonSense said:
The first tank I ever built, to wrap my head around the glass cutting, and assembly process… 6”x2”x2”, 8oz fluid capacity!

Then, the first semi-practical tank I ever built, 4G capacity rimless prism, with a monolithic glass AIO divider… AKA The Ugly Duckling:

This tank is still up and running at my LFS to this day!

Nice build, I'm always a fan of triangle tanks.

56longroof · Aug 11, 2026

The smallest saltwater tank I've had was a 20 long. But I have a 3 gallon AIO I am serious thinking about putting dwarf seahorse in.

JumboShrimp · Aug 11, 2026

Sometimes it would host them-- other times it would just try to eat them as snacks!

saltwaterfish.com · Aug 11, 2026

56longroof said:
The smallest saltwater tank I've had was a 20 long. But I have a 3 gallon AIO I am serious thinking about putting dwarf seahorse in.

Nice if you do you should totally post pictures. For my Pico tanks I had a small auto top off in the form of a upside down water bottle which helped alot with salinity stability. The hardest part with Pico tanks is trying to keep parameters stable since there is very little room for error.

saltwaterfish.com · Aug 11, 2026

JumboShrimp said:
Sometimes it would host them-- other times it would just try to eat them as snacks!

Lol fair enough with how big it is I assume it's also got a big appetite, do you spot feed it?

Gumbies R Us · Aug 11, 2026

30-40oz small in one pico by PNW! We mostly had it be an invert-only tank. Fun tank with very few issues!

saltwaterfish.com · Aug 11, 2026

Gumbies R Us said:
30-40oz small in one pico by PNW! We mostly had it be an invert-only tank. Fun tank with very few issues!

Nice! Do you have any photos you could share?

Kooma · Aug 11, 2026

saltwaterfish.com said:
I personally have set up a couple different Pico tanks in my experience with keeping aquariums. The smallest being a 1 gallon all in one set up that mainly had Zoanthids, a few mushrooms, and a single sexy shrimp. I upgraded it to a 3 gallon after a couple of years, and then a 5 gallon which it currently sits at with a white cap goby, and a green banded goby. I've seen people do setups as small as a 1/4 gallon but this was mainly as a temporary display, and it had me curious. What is the smallest setup you have ever done, how long did you have it setup for, and attach pictures if you have any please!

I have a 3 gallon with a mandarin in it currently. Thankfully the fish eats frozen mysis and doesnt need much space.