parameters and other fish notes

Friday was maintenance for our fishes.

First routine water change I've done on the big tank, so I thought to make a note for myself. It looks like my biological system in there is stable. The water parameters are great: Ammonia below 0.25, Nitrite 0ppm, Nitrates less than 5. I was surprised the Nitrates were so low- either because my few small fish don't produce much waste so there's not a lot of end product in the system, or that the plants are consuming all the Nitrates. Either way, a good thing. I intended to do a 25% water change. Removed 4 gallons (out of a 20 which probably actually only holds 18 gal, if you account for the space taken up by substrate, decor and equipment) but I put 5 back in to get the water to the level I wanted. I think I loose about 1 gallon a week to evaporation. I want to figure out at what point to fill the tank on maintenance day so that I don't have to add any water before the next maintenance day, to keep it at the safe level (if the water level too low filter doesn't work properly, and heater can overheat and crack). Next time I think I will only siphon off 3 gallons and replace 4.

I did make a mistake. The new water I put back in was too warm- even though I had measured with thermometer and tested for sameness with fingers, after adding the new water the temperature rose three degrees in about five minutes. If adjusting temperature, it's supposed to only change by one degree an hour. I was anxious especially for the snail, but both Snaily Snail and the fish seem fine. I kept a close eye on them for a while.

However, something else happened! My fish changed color. It looked as if the tops of their bodies, and the fins were turning a greenish-brown tint. As if the fish had algae on them. My water did have a slight green tint the other day, so I caught two fish in a clear cup and briefly held up to light in front of a white background. No tint to the tank water, definite color on the fins. I swear they used to be clear.

I was alarmed but went to the computer and a bit of searching discovered that a lot of fish change color when they get home and settled in, away from the stress of being in crowded, poor conditions at the store. Also, I gather that with danios, the males turn yellow or greenish color when they are healthy and preparing to spawn. And sometimes the dominant male in the group will have the strongest yellow color. So- my fish are happy! I'm guessing the addition of new water may have triggered the color change.

While I'm mentioning stuff about the tank, I also gave the plants some fertilizer in the form of root tabs pushed into the gravel. I made an error in buying Amazon Sword; I've been informed that this plant can grow up to three feet tall! My tank only has ten inches of height above substrate, so the plant will definitely be too big. Also it needs more food than most of the other plants I have, so I wanted to give it a boost with the root tabs. I don't want to pull it out now but when it gets too big will probably either give it to another aquarist or feed it to my worms.

I have so much to learn about fish still!