Think in stability, not just gallons
A five-gallon aquarium can house a small Neocaridina colony, but small volumes react quickly to uneaten food, evaporation, and temperature swings. A larger footprint also creates more grazing surface and gives the keeper a little more room for routine mistakes.
Keep the stocking modest while the tank matures. Test ammonia and nitrite before adding shrimp, and make sure the filter intake cannot pull in small juveniles.
Make maintenance predictable
Use a sponge filter or a protected intake, add plants and hardscape for surfaces, and feed portions that disappear promptly. Record temperature and water tests so small changes become visible.
Avoid treating a five-gallon tank as a low-maintenance shortcut. If your room gets hot or cold, or you travel often, a larger aquarium may be easier to keep steady.
For your own tank
A compact tank is easiest to manage when the routine stays repeatable. Keep a small log of temperature, water tests, and water changes, and avoid adding several animals or foods at once. If readings swing after ordinary feeding, pause stocking and correct the underlying maintenance issue before expanding the colony.
Use these as general hobby references. Test your aquarium and confirm product guidance before making changes.