7 Dead Fish in 2 Days !!

[Ewan]

In the last 10 days or so I have developed an extremely bad algae problem : I have to scrape the front of the glass every day.

This may or may not be related to a sudden crop of deaths in my tank. Yesterday I had three fatalities and the previous day had four (tetras, guppies, mollies). The larger fish have survived so far but there seems to be a general drop in appetite.

Last night I checked the pH (this was 6.8 so I added some Correct pH) and nitrate (this was 1.0 so I did a partial water change). I don't have an ammonia test kit at the moment so added some Ammo Lock 2 to be on the safe side. I also reduced the light timer to 8h per day in the hope of cutting back on the algae. I'll get some proprietary algae-destroyer tomorrow. Can algae kill fish like this or is the appearance of algae a side-effect of the condition which is killing my fish.

The only thing which I have done recently is add 5 small tetras from a local store (could the water have been contaminated?)

This is really worrying. I hope that someone out there might be able to advise me before things get worse.

Many thanks in anticipation.

 

[Melfice]

The only thing which I have done recently is add 5 small tetras from a local store (could the water have been contaminated?)

Did you pour the LFS water into your tank (The water in the bags with the fish)? It's not a good idea to do so, incase you did.

 

[G_Sharky]

I don't think algae killed all those fish, How long has the tank been set up for and is it cycle? if the answer is no then you should do some reading on the pin topics on these forums on how to properly cycle a tank. And don't add any fish in your tank if your ammonia and nitrite is not at 0. You could do water changes daily to reduce the amount of ammonia and nitrite. Also using Ammo lock could give you false reading on your parameters and if I were you I'd stick on the daily water changes. Good Luck and once you get everything under control this hobby can be very rewarding...

 

[justupgraded15]

Just want to add that if you test your Nitrate levels, it is acceptable for freshwater systems to be up to a 40 ppm reading unlike saltwater systems where they need to be kept close to zero. A spike in nitrates can cause problems though. Do you have live plants in your aquarium? Are any of them new? I am puzzled over your algae problems severity. Were the fish at your LFS in a tank with live plants or other organic matter? If so, there could of been spores of algae that have tried to conquer your tank. Usually algea does not harm your fish unless it is so heavy that it starts to attach itself to the fish or blocks filtration. Definately do a water change (no more than 30%) and go from there. You may also ask your LFS if there has beenin problems in the tank that the fish were purchased from.
J.R.

 

[crazie.eddie]

Algae blooms can be several causes, too much food, not enough filtrations, excess in nitrates.

How big is your tank? What type of filtration do you have? Do you feed alot and often? How often do you clean gravel? How about water changes? How much? Let's look at equipment and maintenance first before trying to figure out some other causes so it does not happen again.

 

[Ewan]

Many thanks for you advice folks.

I did a daily water change for a few days, which soon brought the Ammonia and Nitrites down from alarmingly high levels down to zero pretty quickly. It's scary how the cycle can go haywire like that even in a 6 year old tank. I'll keep a closer eye on the chemistry in future.

I think I may have been overfeeding. I feed twice per day. In future I'll err on the low side when it comes to portions. Also, I was in the habit of doing a 15% water change every 14 days. I'll make this 10% every 7 days in future.

Lessons learnt!!

 

[crazie.eddie]

Also, I was in the habit of doing a 15% water change every 14 days. I'll make this 10% every 7 days in future.

That's a bit small. You can do at 20%-30% on a weekly basis. 10% is good if you only want to do it on a daily basis.

 

[7chanaa]

do a 25% water change everyday 2 starve the algae that should do the trick.

 

[RobbieM]

from general advice I have read i would say not to play with ph, as sudden ph changes can harm fish, also would use that ammo lock cause it will upset the chemical balance. Just keep doing daily water changes untill the nitrate drops.
High nitrate will feed algae.
sounds like you may have been slightly over feeding, I feed twice one day and once the next.
Also a 10% weekly change would prolly be better mate