[ilaizm]

Hi,

I bought two angelfish and two assassin snails from an LFS and added them to my established tank of 10 angel fish. I did not quarantine them. I lost two angels in a week and three more are not looking good. They're staying at the surface, with much less movement and reaction than usual. Two of these three are veiltail and have their tail edges burnt. The 3 of them are also suffering from cloudy eyes.

The two new ones look very healthy and active. I had not lost an angelfish in several months. Setup had no issues.

Water temp is 27 degrees celsius, filter fully cycled, been set up for over a year. Lots of surface agitation so oxygen should not be an issue. Water paremeters: ph 8, ammonia 0, nitrite 0, nitrate 50ppm (i know nitrate is a bit high, but that's high from the water source and was never an issue before).

Did a large water change 2 days ago. Anything I can do to help the 3 which are not looking great? Have not treated with anything yet.

Aquarium volume is 450 litres, apart from the angelfish, i have 15 rummy nose tetras and 10 corydoras. I feed dry food only flakes and pellets twice a day. I do a water change every 3 weeks and change around 60% each time.

Thanks,

Ilai

 

[Plinkploop]

I would do more frequent changes. Angels are sensitive to nitrates. It may be that you didn't notice a decline in their health until the new ones were introduced and stressed them out? Just a guess. When I kept angels I did 2 35% changes weekly for a total of 70% per week. They're messy but delicate fish so their water needs to maintained frequently. I think purigen may help reduce nitrates but I'm not sure as I don't have personal experience using it.

 

[Discusluv]

Do weekly water changes-- every 3 weeks is just not going to work long-term for Angels.
Most likely introduced bacteria into the tank that your current group was not used to. Did you notice some heavy bodily mucus accumulation on the Angels before they died? Did they turn really dark?

 

[Griznatch]

Following this, I always have a hard time with angelfish...