5g Tropical Aquarium

5g Tropical Aquarium
5g Tropical Aquarium

Since I am renting, I cannot really justify a large aquarium any longer. But once the aquarium bug has bitten you, it is hard to let go. So I settled for something manageable - a tiny 5 gallon freshwater aquarium with only a couple of fish and low maintenance plants.


The tank is a 5g (20L) tank with built in chamber for filtration. I added a small heater, and use its tiny pump for water movement.

Mechanical Filtration

There is a large filter sponge in the overflow chamber containing some ceramic noodles.

Chemical Filtration

The overflow chamber contains a small bag of activated charcoal.

Biological Filtration

See section on mechanical filtration. The ceramic noodles act as host for bacteria.


A tiny heater placed in the same section as the return pump provides the additional heat required to keep the tropical fish happy.


I had a CO2 canister hooked up, but it ran out way too quick. It was one of those small Fluval canisters, and the cost would have been around $60 per month so I discontinued it.


The sole source of flow is a tiny pump that causes water to (sometimes) flow over the surface skimming slots of the overflow chamber. This design is flawed as the overflow chamber has holes at the bottom too, and if not blocked by the substrate, the overflow does not skim the surface.


The tank has a LED light strip with two blue LEDs for moonlight simulation.


Nada - the tank is too small for automation.


The substrate consists of 1-2mm grains that I forgot the name of.

Water Parameters

Measured: 15 Oct '20

Ammonia - NH3+NH40
Nitrite - NO2-0
Nitrate - NO3-5 ppm
Phosphate - P0 ppm


I alternate between frozen brine shrimp, bloodworms and betta pellets. The fish are fed daily, but I will skip a day per week.

Maintenance / Supplements

I do weekly water changes, about 40%. I use tap water, and dechlorinator combined with GH buffer. Fortunately I can regulate the heat of the tap water to match the tank. I will clean the glass from algae and try and siphon as much detritus from the substrate I can.

Power Backup

None - these fish are hardy and the tank should survive a couple of hours without circulation.