pulchra's tail

[bathawk]

Noticed on monday my pulchra has a split in his tail now his whole tali is raggid he is alone in the tank checked the water parameters on wednesday ammonia read 0.25 ppm and nitrate 5.0 ppm so I dosed the tank with prime friday and today readings are back to 0 . have noticed that he had been burrowing under some bog wood as some plants have been up rooted water temps are going down now they were hoovering around the 26 c during the hot period now has fallen to 25 c as autumn is now setting was wondering what has caused this his fins are ok I have added a photo the first I took on 31/8/17 and the second today 09/09/17

 

[Madou]

If I had to guess, I'd say water temps.
High water temps tend to cause fungus if exposed for too long. Being in London, and therefore in my season cycle, we're nearing winter, so you should be leaning towards a cooler period, with 20°C as a good middle, leaning towards 15-18°C ish in december/january.

 

[bathawk]

Yes we have had a very hot 3 months and I have been struggling with the temps in both the pulchra and bleheri tanks at one point they were topping 27 c and I was using frozen bottles of water in the tanks to try to cool them down although the bleheri seems fine I have put some melafix in to see if it will repair his tail