Joeinlondon

Dear All

I have a 200L NPT. It has been running well since late May (so about 5 months) with good plant growth, and no insuperable algae problems. However, I am still seeing quite a lot of 'flashing' from my glass blood-fin tetras, and a bit of headshaking from them and the cardinal tetras that are resident. Observation leads me to believe that the fishes' irritation is in the gill area: this is the part of them that they try to rub on leaves etc.

Now - I also have running a 40L prototype NPT, started long before the 200L. I observed exactly the same behaviour in the micro-rasboras (Boraras brigittae), i.e. flashing and irritability. After a few months this behaviour suddenly stopped. I believe that the aquarium had reached some form of 'super-maturation', or alternatively any last vestiges of irritants in the soil (which was John Innes No.2 compost - very gaseous at the beginning) had been removed via 'nutrient export' via pruning.

However - wanting to avoid the initial eruptions and gaseousness of the prototype, for the 200L I used a packaged 'topsoil' from the garden centre, thinking it would be more inert - more soil-like, rather than compost.

Also - I explained this problem to a very knowledgeable and experienced marine LFS owner, and he suggested that it might be 'free ammonia' - which I confess I had never considered before. He asked me if the flashing was worse during feeding, and while I cannot say for certain, it may well be.

Finally - the other differences between my prototype 40L tank and the 200L tank are that (firstly) with the latter, in order to get food through the 'tetra corridor' and down to the cichlids, I often swirl flakes or frozen food in a small cup of RO water, which is then poured in to force the food particles downward. I think it is a slim chance, but could the tetras diving into this mix of waters be somehow burning their gills? To be on the safe side I still treat the RO water with a tiny bit of conditioner. The second difference is that the 200L tank is open topped. This means that much water is lost in evaporation, and I must have to put in about 5L of water a week to top it up (again, cold RO water). Again - might this mixing of water be affecting the tetras? Thirdly - the 200L tank is still running carbon, because apart from this flashing, everything is going well and looking good, so I am loathe to change the system. And presumably, if there were any impurities still leaching from the soil, the carbon would help remove them.

I have not had any losses from this flashing and irritation, but my experience is that until this flashing goes, the tank is not 'super-mature', and will not support more delicate fish, so for me this issue definitely needs resolving.

As ever, any insight would be greatly appreciated.

Joe

LVKSPlantlady

Maybe try mixing the food with water from the tank Instead of the RO water?? And for the water replacement try mixing the new RO water in a bucket with old tank water 1:1 before adding it all back in, If the RO water mixing in the tank is the problem this should fix it. But I'm no expert!

Joeinlondon

Ah! Now I did think of that, but breaking the surface of the water with said plastic vessel without the positive re-enforcement of food appears to make my cichlids think that they are about to be eaten by the cup-monster, and sends them scurrying for the back of the tank.

Mixing top-up water with tank water is a good idea, although having to get the syphon and bucket out is much more of a pallaver (and intrusion) than merely topping it up from a bottle at night. Topping the 40L up (although relatively in much smaller quantities) with the same bottle appears to have no bad effect - so I'm doubtful whether this is the real problem.

LVKSPlantlady

They will get over the cup in a few weeks maybe even months, Once they realize that the food is coming next...

Dustymac

Hi Joe,
It seems to me your flashing might be the result of a non-lethal bacterial or parasitic infection. It started and ran it's course in the 40 liter, then it jumped to your 200. What do you think?

Jim

dwalstad

I wouldn't worry about topping off or how you feed the fish. A few seconds of exposure to dirty water isn't going to hurt anything. Rather, it sounds like a low-level infestation by parasites or bacteria. My guess would be parasites?

One or more of the fish could have had a low-level parasitic infestation when they were introduced into the tank. Since then its spread.

As to what to do, it depends on how bad you think the problem is. You could try a quick treatment with an anti-parasite medication. Of course, the ultimate is a fish vet diagnosis. It doesn't sound like an emergency situation, just an irritation...

LVKSPlantlady

well I was way off, but you have to start somewhere...oh well that's why I'm no expert!

Diana K

I regularly top of my tanks with straight tap water with chloramines, cold out of the tap in the summer. In the winter I run a little warm water, but am not too picky that the temperature matches. I will top off hard water tanks with soft water. I add aquarium fertilizers into the flow from the filter, so it is diluted pretty fast, but sometimes the fish swim through the more concentrated fertilizer with no problems.

The key here is SMALL % of new water, colder, different mineral level, toxin, fertilizer is a momentary thing, immediately flushed out ... The top off is never as much as 10%, or more often than once a week. For water changes I am much more particular that the parameters of the new water match the old water to the best of my ability. I do not think that a cup of RO water added to the tank with food, especially spread out across the tank is in any way responsible for the irritation you are seeing.

I agree with the other people. More likely to be a parasite or similar irritation.

If it is related to water chemistry I would think you would see some test results. Ammonia can cause irritation at levels as low as .25 ppm, and test kits read that low. Changes in pH outside the tolerance range of the species, or pH incompatible with the species can cause irritation. Again, your test kit would show this. For most tetras a pH anywhere on the acidic side of neutral is fine from about 6.0 up to about 7.5. There may certainly be fish with a more specific requirement for pH, but most fish are not as picky about pH as long as the mineral level (GH, KH, TDS) is right.
Salt (Sodium chloride) can be an irritant to some fish. There are tests for low levels of salt, but you would know if you are adding salt to your freshwater tank.

There might be something else coming out of the soil, but something that we do not test for. The only way I can see to prevent that is to run the planted tank for at least a month, with several water changes to allow whatever it is to get removed from the tank.

Joeinlondon

Dear All

Thank you for your responses.

I concur that it is a parasitical infection. Not thinking about water quality I looked at my fish again and found very small greyish slimy areas, which I had not seen before. I am treating with an anti-slime/velvet medication from Interpet.

Hopefully this will do the trick.

Thanks again

Joe