Harlequin rasbora with one red gill

[redgillrasbora]

I have 10 Harlequin Rasboras in a 60 liter tank (water temperature is 23 °C, pH around 6.5-7, there is an adequate filter, and the tank is somewhat planted): 5 of the HR:s came almost 4 weeks ago, the other 5 one week ago. Yesterday I also added 5 Cherry Shrimps + their water (bought from another hobbyist).

The rasboras have been quite aggressive the whole time, chasing and nipping each other. Today I noticed one of them has a red gill - could it be irritated/infected or possibly an injury from nipping? Or could it be some illness/parasites? The fish looks fine otherwise, has bright colours and is as aggressive as usually. Actually it looks like it’s trying to show off to another aggressive fish. I’ve seen some of the fish getting really pale earlier, presumably because of the harassing, but the injured one is really dark.

Shrimps seem to be fine, and both nitrites and nitrates are down in the tank. I started wondering, did I accidentally bring in some parasites from the shrimp seller’s aquarium. I know I should have quarantined, but I don’t have another tank.

Another issue is the cycling. While the tank is fully cycled now, it wasn’t when I brought the first HR:s in. I trusted Prodibio Bio Digest (bacteria product) to cycle the tank immediately, which it didn’t do, so I had to keep adding bacteria and changing water every day for two weeks before nitrites went to zero. During that time the 5 HR:s must have been stressed. That could have made them weak and susceptible to diseases.

Does anyone have some advice for me? I would be very grateful for help!

 

[JuiceBox52]

Could be any of those things. What are your exact readings for ammonia, nitrite and nitrate?

Do a 75% water change every day for 1 week. This will help if it is chemical burns as well as hell and injury heal

 

[redgillrasbora]

I don't have an ammonia test, but nitrites are zero and nitrates either zero or very close (it's a bit hard to say exactly, I'm using test strips).

Why do you think testing ammonia is important? I could go and buy a test for that tomorrow if you think it could be helpful.

 

[JuiceBox52]

Testing ammonia is important because it is what the fish excrete (the equivalent to our urine) and decomposition of plants, feces and uneaten food cause ammonia. Ammonia is highly toxic to fish, red or bleeding gills is a classic symptom of ammonia poisoning.

In an aquarium it is vital that ammonia stays at 0

If you buy a test kit get the API master test kit. It's more expensive but Worth the price for sure. It's also more accurate than the strips

 

[redgillrasbora]

I've seen nitrites go up during the first couple of weeks, and then nitrites went down and nitrates up. That seems to suggest that the cycling worked as far as I can tell. Also, only one gill of one fish seems red, and shrimps are fine, so it could be something else than the water.

Anyway, testing ammonia would give me the answer. Master test kit looks really pricey, though!

 

[cupofjoel]

I've seen nitrites go up during the first couple of weeks, and then nitrites went down and nitrates up. That seems to suggest that the cycling worked as far as I can tell. Also, only one gill of one fish seems red, and shrimps are fine, so it could be something else than the water.

Anyway, testing ammonia would give me the answer. Master test kit looks really pricey, though!

On another note. They shouldn't be showing so much aggression. If your stocking allows for more numbers I would add more Rasboras. This would reduce aggression.

 

[JuiceBox52]

I agree with cupofjoel. Missed that! Aggression is less of a problem in large numbers, but you may not have enough room in a 15 gallon