Thanks, both. As mentioned in the first paragraph of the original post, there is chloramine in the tap water, hence my dilemma.
A bucket of water has actually now been standing for ~30 hours and pertinent test results are as follows:
JBL 6-in-1 test strip:
0.8 Cl2 mg/l ie chlorine [possible results are 0, 0.8, 1.5 or 3.0] which is accompanied by a warning symbol – rather difficult to read, though, but definitely seems to be some chlorine still present.
API ammonia test strip (NH3/NH4+):
0.5 [possible results are 0, 0.5, 1.0, 3.0, 6.0] although the actual result is difficult to read.
JBL ammonia/ammonium test (NH4):
0.2 NH4 mg/l (ppm) [possible results are <0.05, 0.1, 0.2, 0.4, 0.6, 1, 1.5, 3, 5] – this is definitely the easiest and most clear-cut to read of the tests.
Cross-referring to
https://forums.thinkfish.co.uk/fish-health/tetra-with-unhealed-injury/msg35240, I’m thinking that the best course of action is probably:
* to extend/prolong the eSHa 2000 course by a couple of days (ie dose on Sat & Sun) as the detailed leaflet advises if some improvement – it’s not clear that there’s necessarily any improvement but at least the fungus doesn’t seem to have spread or got any thicker/coarser and so at best may have halted;
* meantime (ie on Fri eve), add Seachem Prime to the aforementioned bucket of water which has been standing, and, if I were to perform a water change on Mon, the Seachem Prime in that bucket ought to have done its job and thus not be problematic if any subsequent treatment course were to be administered;
* if required, I could then administer either another course of eSHa 2000 or another medication after that (although, ideally, the problem will be resolved by then), having run some carbon in the filter beforehand to remove remnants of the original treatment.
Thoughts? Thanks.