paradise fish is still sick.

Question
QUESTION: i have a single paradise fish in a 25 L tank. he took sick a couple of weeks ago over easter. originally i thought it was ammonia poisoning but since i have done everything suggested and also started treating him for fin rot in case because his fins did look a little red almost like blood. he was ok last week and was almost back to normal. but tonight he is behaving different again. much slower and sitting on the bottom occasionally also some of the redness at the bottom/roots of his fins have come back. it almost looks like blood. i was using API melafix, and doing water changes every week only a couple of literes. What else can i do to make him well. Is the fin rot perhaps needing a different medicine? i am adding de chlorinator and that stuff to the water when i add a little more.
please help me again!

ANSWER: Hi Kelly,

I realize you have just one paradise fish in a tank, but your tank's water is filthy, and this causes poison to the fins.  The shredded fins with red streaks are Ammonia and Nitrite poisoning.

Adding water isn't sufficient.  We need to change water at a rate of 25% every other weekend.  With you, 50% needs changed today, and then 25% every 3 days for a week.

Melafix is worthless for this.  

A couple of liters isn't enough water change...you need to clean the tank's gravel and filtration unit as well.  I suspect you don't use a filter, but if you do, then spotlessly clean it.  If you don't use one, get one asap.  The quality of the fish's life will drastically improve.

For fins...they will grow back once his water is taken care of.

Happy fish-keepnig and I will cross fingers for your fish, Kelly. :)

---------- FOLLOW-UP ----------

QUESTION: i did a water test and all the tests are normal, i do have a filter that i keep maintained well. also do the water changes every 7 days. today hes more active, although i was just watching him and he was swimming near the bottom of the tank and then what looked like he choked and started spitting out bubbles then surfaced for air. the ph, ammonia, nitrate levels are all normal.

Answer
Hi, just to reassure you that this is ammonia/nitrite poisoning, if there is anything above 0 on the stips (even if it reads "safe"), it is not safe.  The fish is suffering very typical symptoms.  The red lines are indeed from this.  Ammonia may show okay, but what is nitrite?  Nitrates may be below 10ppm, anything above is too high.

For some reason, people use test strips.  They test for several things, but many only have a range of levels with guidelines. They are inaccurate.  They are not safe, because where it says the fish may have a safe zone, in Nitrites and Ammonia...they are wrong.  ANY nitrite or ammonia (any color at all) will cause poison in more susceptible fishes.  Therefore I still recommend changing his water since his symptoms are very typical of this type of poison.

Another thing that can cause this is chlorine.  Chloramine and chlorine are even found in cities and places using well water.

If he's choking, it's time for another water change. Once a week is good.  How often are you changing his filtration unit?  What kind of filter is on his tank?  Make...model?  Even Bettas require filtration. :)

Without it, they are just swimming in poop water, even if changed weekly.

Please feel free to send me photos.  I am interested in seeing the tank, setup and maybe seeing an image can spark another idea what could be poisoning him, but his symptoms are that of poisoning.  Usually, this type is chemical.