Five Gallon Nano Aquarium – Part 2 “Dark Waters Ahead”

Last week I posted about a new 5.5 gallon nano aquarium I picked up at the second hand store and turned into a Walstad tank. A few days in I ended up changing a good 90% of the water because ammonia was spikingĀ at 4.0 ppm! The water was pretty cloudy and full of tannins from the soil. If you remember, I lamented the loss of those beautiful tannins. Well guess what… they came back!

The water is getting nice and dark again. There must be plenty of tannins left in that soil!

Since last week I have added a ton more frogbit and moved the HOB filter from my 3 gallon nano tank to this one in hopes of tackling the excess ammonia coming from the soil, at least until the sponge filter can fully seed with bacteria. The day after the big water change, the ammonia came in at 1.0 ppm, still very unsafe for fish, but a vast improvement. A couple days later it measured 0.5 ppm. A real, measurable change! So I used my trusty 6-in-1 test strip to get a reading on the nitrites and nitrates. There was a big jump in nitrites (from 0 to ~1.0 ppm). Nitrates are still unmeasurable, but more than zero, evidenced by a tiny amount of pink (but less than the 20 ppm marker shown on the test reference chart). Then the next day the ammonia was measuring at 0.25 ppm, the nitrites at almost 5.0 ppm and the nitrates still just shy of the first marker (20 ppm). Things are looking good. If I can get all my nitrogen converting to nitrates, then I’m on easy street.

I’m also happy to say the water is so far showing no cloudiness! That water change got rid of all of the silt that was floating around from the gravel and whatever else was in there.

We’re movin’ on up!

I also added a stick of bamboo I bought on a whim, when my wife and I were at Ikea looking for a dresser. I figure with all these nitrates coming down the road, the frogbit might need a hand soaking it up.

I’veĀ been thinking about letting this tank go emersed. I’ve already planted a few Amazon Sword plants. Those with this bamboo could be interesting if they grow up out of the water. I think that would go well with the black water and some gnarly driftwood. What do you think? I’ve added some Anubias on driftwood to the tank to help fill it out.

One of my Amazon Sword plants. It’s already growing some new leaves.

I think the blackwater against the sunlight from the window looks very cool. Makes me think of an alien landscape. Below are a few detail photos:

C’mon sponge filter. You can do it!
A nice view of the thick frogbit mat and HOB.

I ended up moving my White Cloud Mountain Minnows from my patio pond to this tank. After conferring with some fellow fishkeepers, it may get too hot outside for the coldwater fishes. I plan to keep the 5.5 unheated for their benefit. I know they are a fish that appreciates room to swim, so this may be a temporary situation. We’ll see how they do. They’ve been exploring and eating copepods and hydra as they go. So far they seem to like it.

Here are two of the White Clouds. I changed the water one last time before adding the fish. Tests showed the tank was fully able to digest ammonia, and nitrites were being converted to nitrates. I’ll keep my eye on it.
Here is the tank after one last water change and with fish newly added. You can also see the new driftwood and anubias.

Last week I planted a stem of rotala rotundifolia horizontally in the gravel, and it’s finally showing signs of life!

So proud.

Lastly I added something else… amphipods! You may know them as “scuds” or “side-swimmers”. They are funny little shrimp-like creatures that feed on waste and leftover food. The minnows enjoyed chasing and eating the smaller ones, while the adults were a bit too big to swallow.

Here two gammarus amphipods are mating on some hornwort. Looks like I should have plenty of live food for the minnows.

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