Just wanted to rack some brains for any possible answers..
I have a 190L Tropical Tank which has been established for over a year now, has a very mature external filter running and the internal filter (Juwel Trigon 190) also mature and running also with air pump in the tank.
Now i keep having problems with regular reoccurring fungus which i treat and seems to go away and then seems to come back around 8 weeks ish later?
Temperature is stable at 26*c, water quality seems ok Ammonia; 0ppm, Nitrite 0ppm, Nitrate range between 20-40 max and PH is 7.8
I change approx 30Litres once a week (Doing a deep gravel clean as i go) and feed very carefully with the amounts as not to over feed, and i clean all the filters in dirty tank water etc.
Am i doing something wrong here as i can't figure out why this keeps happening, it usually starts first on my black mollies then spreads to the other fish in the tank which are as follows; 2Black mollies, 6 Neon tetra, 4 harlequins, 2 clown loach, 1 bristle nose and 3 platys,
I haven't added any new fish to the tank in around 6 months and i haven't lost any either just seem to be battling the fungus!
There may possibly be an issue with Phosphates as i am seeing Black feather like algae which i have read could be linked to high Phos levels, could this have an impact on the fungus?
Do you know your water hardness and alkalinity (gH and kH)? If the water is too soft mollies can be very susceptible to outbreaks of fungus and other skin infections.
Although your tests seem OK I'm suspicious that nitrate may be higher than you think (especially if you're using the API liquid test) as 30L a week is not much water to be changing. We'd generally advise at least 25%, so closer to 50L a week for your tank.
Which medication have you used to treat the fungus?
Thanks for your reply, I'm not sure what the hardness is but i will get that tested and find out, That could well be the case as i am using API liquid test kit is there a better test you would recommend?
I have used Melafix and Pimafix in conjunction which has seemed to prove pretty effective and clears it quite quickly,
I will try changing more water and see if that helps, i also alternate the cleaning of the filters i.e internal filter alongside water change then the following week clean the external filter with water change on a rolling basis,
The Nutrafin or Sera nitrate tests are easier to read as they don't default to all the same colour above 40ppm like the API one.
Melafix and Pimafix are very mild and I think maybe they're not getting rid of the fungus completely which is why it keeps coming back. I would try a course of Esha 2000 which is a very effective anti-bacterial and anti-fungal medication.
Sorry only just seen this post, I have also done the same 2 rounds of Esha and still battling with fungus, i have stepped up the amount of water being changed - now doing 25-30% weekly and cleaning both filters weekly in case that may be causing the nitrates to rise.
Currently the fungus does seem to have gone but weirdly it sometimes appears out of no where - mainly just on my black mollies and thankfully i haven't lost any fish to it.
I was going to add some aquarium salt which may help as a general tonic but have read i shouldn't as I've got Clown Loaches and it may irritate their skin.
Did you ever find out how hard your water is (should be on your supplier's website under "water quality in your area")? The reason I'm asking is that you have clown loaches who need soft water and mollies who need very hard water. If the water is soft, the mollies will be very susceptible to infection and often will produce excessive slime coat which can look like fungus.
HARD WATER The area supplied by Affinity Water has 'hard' water. The hardness occurs naturally and is characterised by the presence of high levels of calcium and magnesium, which are good for healthy teeth and bones. CALCIUM 128 mg/l Calcium is the principal constituent of hardness. TOTAL HARDNESS 320 mg/l Total hardness is usually expressed in terms of calcium carbonate and is measured in milligrammes per litre (mg/l) which is the same as parts per million (ppm). The recognised classification scheme we are using is: 0-75 soft, 76-150 moderately hard, 151-300 hard, 300+ very hard. Your water is very hard.
Strangely the clowns have never had any issues and always seem bright and perky in their activity around the tank, they also feed well,