Fish death/ green water

[dena]

We have had our 4ft x 18in x 2ft tank set up for over 3 years now and have had no major problems. Over the last year we had added some lovely Discuss fish, and in the future were hoping to change to a marine tank. Everything was fine. We had 3 Discuss, 1 large Silver Shark which we had since he was only a couple of inches long but grew to about 8 inches long; we have Clown Loaches, a Pleco, a figure of 8 puffer ( living in soft water) , Neon Tetras, Coridoras (is this spelt right)? and a number of other fish that I am unsure of the names of!

We had our tank set up originally with an underground filter but changed it to 2 x Fluval 4 filters because we wanted sand for our future marine tank.

We have recently decided to include an external filter because we thought it might work better. We bought a Rena filter and were advised to keep both internal filters in place until the external filter was matured. The external filter has been in for over 2 months. During this time, or shortly after, the tank turned green, so green that we could not see any fish at all. We were advised to add some 'tea bag' like anti phosphate substance to the external filter.

With the internal and external filters still in tact for over 2 months and with green still visible but a lot better we decided that we would take both internal filters out and leave the external filter running on its own. We did that yesturday. This morning, to my horror, the external filter was not filtering properly, all fish still alive were at the top of the tank and my 3 Discuss and my Silver Shark were DEAD!!

We think that we have been given the wrong advice with regard to the 'tea bags', and think that maybe the bags were in too long and clogged up the external filter. Whilst the internal and external filters were working together everything was OK but as soon as took the internal filters out, fish were DEAD. I am extremely upset. Can you advise us as to what may have gone wrong. We had obviously tested the water and found that everything was high, so I did all the right things, I added amo lock, we took the tea bags out and the filter works properly now - we think, and the fish seem to be a lot happier than they were this morning. I am not sure whether or not we will have more deaths yet. But I have lost some very nice fish. What do you think has gone wrong and what should I do?

With regards,

Dena Richardson

 

[Wasserpest]

Hi Dena,

With the fishes you list, and "a number of other fish" ?? your tank might be overstocked. This especially affects Discus, which are very sensitive to water impurities. They are not good community fish for that reason... need a large tank, water closely monitored and changed frequently...

You don't list what kind of Rena filter you bought, if it is an XP3 for example it should do some good filtering, but it seems like there is some problem with it, and removing the two other filters got the water quality to drop suddenly... there they go

What filter substrate do you use in the Rena? I doubt the "teabag-like" stuff will help with your green water... usually this is something that a tank goes through and is then immune.

 

[dolphin]

Hi Dena

Sorry to here of your losses.

Which XP filter do you have?

You said that all your readings were high one day after you removed the internal filters. This would mean that the levels were high prior to removing the internals. Ammonia and nitrite take time to build up, without adequate filtration. This would mean that you did not have enough filtration, or your tank was over stocked.

Did you test the water prior to removing the internal filters?

I run a 48x20x24 with a renaXP3, (the only original media that is in it, is the foam. I have added some ceramic sponge for biological filtration), with 8 discus, 6 clown loaches and a small rubber mouth catfish. I never check my reading, as two of the discus spawn and hatch eggs each week, so the water is of top quality. So if you do have a XP3 then it is ok for the size of the tank you have.