The Planted Tank Forum banner

Small Tanks Don't Cycle? What??

977 Views 7 Replies 5 Participants Last post by  cl3537
Hello all,

I'm new to the aquarium community and am trying to get some reliable information regarding cycling.

I currently have a 5 gallon planted tank (fluval spec V) which is generally doing well. It has been running for a few weeks. Unfortunately, I didn't have the opportunity to cycle this tank at all. The tank ran for about three days with plants only (and prime treated water) and then a betta was added. I do not see any signs of stress and the fish generally seems happy.

My understanding was that the tank must be cycled before fish are added. I am aware of fish-in cycles as well. Recently, I've been reading that tanks under 10 gallons do not cycle, or do not require cycling. I've read that water changes never allow the bacteria to grow effectively when the tanks are this small, leading to unstable conditions. Is this the case?

With the rise of the nano and desktop tank, I find some of this information hard to believe. Will my tank crash? Should I be doing more water changes? Do smaller tanks require more water changes/cleaning/maintenance than larger ones?

Also, I am awaiting a liquid test kit, but my parameters (using test strips) are reading 0.5ppm nitrite and 40ppm nitrate, with moderately hard water and a neutral pH. I'm trying to figure out what I am supposed to be looking for in these parameters. I realize that the nitrites should be 0 and am doing regular 50% water changes.


P.S if anyone has a similar 5-10g planted setup, what is your maintenance schedule?
1 - 1 of 1 Posts

· Registered
1,418 Posts
All tanks cycle to a degree....or not. Aerobic beneficial bacteria colony(ies) are relative to the available food supply and oxygen. Nitrosomonas converts ammonia into nitrite and nitrospira converts nitrites into nitrates. HOWEVER, in a small planted tank, or even a larger heavily planted tank, the development of the BB may be inhibited. Why? Plants will use ammonia as their nitrogen source so with little bio-load, the plants may use the ammonia instead of BB. This is a good thing, as it results in lower nitrates.
I have an experienced hobbyist/friend that never cycles a tank per se....because he has fast growing plants that handle much/most of the ammonia and he initially stocks the tank low. Oh BB eventually develops, but to a much lesser degree than might otherwise be the case.
In any case, tank size is irrelevant relative to the nitrogen cycle.
1 - 1 of 1 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.