I've gone ahead and reduced the temp of my tank and will do daily water changes. I'm a bit unsure of which medication would be best. Is there anything that you could suggest that's available in the UK?
Overall I was wondering what the best course of action would be. I have a small tank lying around that I could turn into a quarantine setup. However I was unsure as to whether or not I should be separating and treating the specific fish that's sick, or given the fact that I've had a few deaths now (the rest look fine at the moment) that I should be keeping everyone together and treat the main tank.
I’m not in the UK so can’t really suggest what’s likely to be available (check online as well)
BUT
anything added only has the ability to improve mortality rate not actually treat/inhibit (most) Columnaris strains
Often guppies will respond positively to the addition of NaCl (your plants maybe not so well), so you might try adding salt (NaCl), begin with 1Tablespoon per 37litres, then after 12-24h increase to 2T per 37litres - you can continue increasing this salt level, but if you don’t see any improvement at this stage, increasing salt will unlikely have much effect
(the salt may alleviate “velvet” or other secondary infection symptoms, it won’t negatively impact the Columnaris)
A previous post I made
in this thread
Columnaris disease in fish: a review with emphasis on bacterium-host interactions
- Annelies Maria Declercq
- Freddy Haesebrouck,
- Wim Van den Broeck,
- Peter Bossier and
- Annemie Decostere
Veterinary Research. 2013 44:27
https://veterinaryresearch.biomedcentral.com/articles/10.1186/1297-9716-44-27
This review article is hosted on several sites, some of which include full access
Without access to meds that have proven Columnaris activity, optimum water conditions are your best bet
You’ve already decreased temp, which is good
Softer water will also improve survival rates (pick up some RO to dilute with tap if you’re in a hard water area)
Slightly acidic pH also seems to benefit fish over Columnaris
Increase surface movement - ie anything that optimizes oxygen levels in water is beneficial to fish as C invades gill tissue
Vacuum substrate as much as possible
Rinse all filter media, clean filter hoses of any sludge
I’d use activated carbon to remove any medications that have been added - they will only act as fish stressor
(& most sequester oxygen)
AND remove any possibly infected fish to a separate tank (or food safe bin) set up with bare bottom - they will act as a significant infection source
I’d actually remove all Bettas and Danios, also consider rainbow isolation (though I’d keep them separate from the Bettas and Danios)
Be very careful not to cross contaminate from isolation tanks, back to main tank - separate nets, water change equipment etc - also have a physical separation between tanks
At this time, sounds like the fish you are losing are among those species that are more “sensitive” to C infection/higher mortality (even with suitable medications etc, there is always some % mortality)
As you’ve only the 8 guppies in your Fluval Edge I’m not sure I’d worry overmuch about fish separation in terms of maintaining water quality and minimal bioload
One issue that many claim about the Fluval Edge series, is poor oxygenation of the water (based upon anecdotal observations not any actual oxygen measurements (I’ve seen)), so I’d suggest dropping the water level and possibly adding an air stone/pump - though if you can arrange for the filter return to “splash” that would also address this issue
You don’t mention actual size of your “small tank”
- I’d actually be inclined to remove the healthy seeming guppies to a bare glass tank (you can add some unused plastic plants or a newly purchased plant (from a fish free system, especially Aquarium Gardens which maintains a hydroponic style holding system for their potted plants) while sorting out the Edge
- realistically, I doubt the Guppy in video will recover - unless he has a food response? - though I understand a reluctance to euthanize. Do you have one of
those net breeders? (there are various branded versions) this can be placed high in the tank so that there is some gentle current crossing through - this will improve water movement across guppy gills and should help his increase oxygen levels (making him more comfortable)
