A question about parasites and humic acid…

[An_Outlier]

Hello.

I’m new here, obviously; I’ve been lurking here on and off, but I have decided to make an account.

I have a parasite problem right now in a 10 gallon tank housing two P. anjunganensis and a small shoal of Boraras urophthalmoides (primarily as “dither fish”). Everyone has been healthy and tank parameters are up to par, but on Sunday (last weekend) I noticed that one of the boraras had some tiny lesions/cysts on its body. I examined the other fish, and while the “Paros” seem to be fine, I had to isolate five of the boraras because they either had obvious similar cysts/lesions or looked like they were developing them.

It took a couple of days to isolate all of them because the last two were very hard to capture (the tank has a very complex hardscape with tangles of moss, java fern, and ceratopteris, plus floating plants), but now all are isolated in a “hospital tank” and I am treating them with a formalin/malachite medication at a reduced strength.

I am not quite certain what these cyst-like lesions are being caused by, but I am certain that it is a protozoan parasite, because everything about the cysts/lesions matches. Furthermore, one of the boraras died, and prior to its death I removed it from the hospital tank (it was the “runt” of the shoal and it had a heavy load of encysted parasites relative to the size of the fish) and took a skin scraping to put under the microscope. Sure enough, I saw swarms of tiny organisms escaping from cysts and moving about the slide in loose aggregations.

I suspect that this problem arose from one of two sources/events:

1) I live in Oregon, near Portland, and we had a heat wave sweep through over the last two weeks; temperatures soared to near 100 deg. F, so I unplugged the heaters on all of my tanks to keep from overheating the fish. The heat wave then subsided, and after it appeared to have gone I plugged the heaters back in, but the water still cooled to roughly 71-72 deg. F for a short time. If the parasites were already in the water, this may have reduced the immune activity in the fish just enough for them become infected.

2) I recently (about a week ago) purchased some Ceratopteris pteridioides plants from a new aquarium shop that opened up very close to my house. The shop is run by a highly reputable fellow who has been active here for quite some time, and there were no fish in the tank with the plants, so I thought nothing of quarantine. Given the current timeline, it seems possible (unfortuntately) that I acquired the parasites from these plants.

In either case, I have no guarantee that the tank (current occupants are now three boraras and the two Paros) is parasite-free. I recently purchased a bottle of peat extract from a garden shop in the hopes of using it to help keep the water conditions I need going, and I decided to refresh my memory about humic acids here:

http://www.skepticalaquarist.com/humic-acids

This article mentions the following in the third paragraph:

“humins affect the cycling and bioavailability of chemical elements; they repress many bacterial populations and affect the zooplankton: acidic blackwaters rich in humic acids have characteristically low populations of bacteria and a depauperate zooplankton.”

Since common protozoan fish parasites have a free-swimming stage that needs to attach to a host (plus another stage that rests on the substrate or other solid surfaces), and one could consider the free-swimming stage zooplankton (and neither the substrate-bound stage or the free-swimming stage are protected by host tissues), could these be susceptible to a reduced pH brought about by additional humic acids?

I could easily bring the pH of the tank down to less than 6.0 over the course of a day or two. I have been extremely busy lately, so I have not been able to closely regulate the water parameters, and the pH is slighly above 6.0 and I do not have as high a tannin/humic acid concentration as I would like. The fish would obviously prefer this, but it may be a creative way for me to make life difficult for any other parasites that may be attached to fish undetected or hiding elsewhere.

I decided to ask this question here because this board is full of people who have to play around with humic acids by definition, and I was wondering if anyone knows if they can inhibit protozoan parasite activity in a tank with fish that prefer blackwater conditions anyway.

[Pavel Chaloupka]

Hello and welcome,

Just a first quick help.

1. Please do not use peat extract from garden shop unless you make sure it does not contain any additinal fertilizers or other substances. It is very likely it will not help you adjust the pH, I would assume that commercial peat extract would be buffered so that it is not too acidic. That of course means it would be useless for bringing the pH down.

2. Humic substances will not harm the parasites, but if you use the right humic substances, they will of course help the fish, lower the stress and help heal the skin. The lack of zooplankton in black acidic water is mostly caused by the lack of bacteria in the first place. In case you will be forced to treat the fish, avoid using medication that contains malachite green in acidic water. The toxicity goes over the roof. I would try to use quinine based treatment. Also if you use something that would truly contain humic and fulvic acids or their salts, keep in mind that these humic substances really influence bioavailability of many substances and for example pesticides administrated with addition of lignohumate have the same effects with much lower doses. The same may apply for the treatment. I would like to help more but my Paro experience is not extensive enough + even thought I have pretty extensive experience with other black water species I never had to treat any of them for external parasites. Most of my other species are extremely susceptible to commonly used treatments and I just have to be very careful to not get in such situations. Also “humic substances” are super complex topic and we know very little about them, besides their positive effect on plants and animals. I think Peter and Bernd will be able to give you more practical advice with regards to possible treatment.

3. In case you want to have other fish with Paros, go for some really black water Boraras species, uropthalmoides are not the case and you keep both fish in borderline conditions. One more advice if you do not mind. Never trust any fish or plants no matter how famous and known is the breader. As it is with humans, some populations are highly susceptible to certain viruses, bacteria and parasites, some are not or not nearly to the same extent. The fact that you have not seen fish in the tanks does not mean that they were not in there short time before and these do not have to be fish, for example snails are carriers of many diseases transmitable to fish. Quarantine everything always.

[Bernd Bussler]

Yes I agree with you, snails can transmit diseases, living in black water hardly snails and other micro-organisms have it too hard. I have not yet lost no Paros by parasites, rather byreacting and injuries while catching out even though I several times a week, my own food which also include native fish catch in different waters. Paros are in good care really tough and more likely to die of old age as from diseases. 🙂

[helene schoubye]

I also keep small boraras in some of my parotanks, – mostly boraras maculatus, – and I had in one instance a terrible outbreak of something which maybe resembles what you describe. The boraras was infected with lots of small cysts, – I actually thought it was ‘ick’, – and I remember it came after a change in temperature as well.
It was a small tank, – in fact I had one paro in it and 3 boraras. I didnt medicate at all, mostly because I had no idea how to treat tiny fish like boraras, – I have not a lot of faith in medication for so tiny fishes, and I was worried about affecting the paro with medication.
So I didnt treat, – and I did loose the boraras, – but the paro was totally unaffected even the outbreak was very bad. The paro survived and lived long after and it didnt affect any other tanks later.
It was not of course ideal not to treat, but this is the only time I have had any experience of this kind involving both paros and boraras. Normally I do not see this kind of sickness with any of the species.
The paros can get odinium, this happens now and again, – but other sicknesses, – it seems very rare.

[Bernd Bussler]

Now I see it like Helene, my Paros have no co-inhabitants and I have where I usually Paros seen in the 20 years no major Kankeiten unless they have become really old, then they get sometimes ascites bulging eyes, or curvature of the spine, but in Age we will get the one or the other disease in Paros, it is the same. Otherwise, they really are not sensitive and are more tolerant even in water values, unless you want to breed, then you need one or the other kind of a little more attention.

[An_Outlier]

[quote=”helene” post=4845]I also keep small boraras in some of my parotanks, – mostly boraras maculatus, – and I had in one instance a terrible outbreak of something which maybe resembles what you describe. The boraras was infected with lots of small cysts, – I actually thought it was ‘ick’, – and I remember it came after a change in temperature as well.
It was a small tank, – in fact I had one paro in it and 3 boraras. I didnt medicate at all, mostly because I had no idea how to treat tiny fish like boraras, – I have not a lot of faith in medication for so tiny fishes, and I was worried about affecting the paro with medication.
So I didnt treat, – and I did loose the boraras, – but the paro was totally unaffected even the outbreak was very bad. The paro survived and lived long after and it didnt affect any other tanks later.
It was not of course ideal not to treat, but this is the only time I have had any experience of this kind involving both paros and boraras. Normally I do not see this kind of sickness with any of the species.
The paros can get odinium, this happens now and again, – but other sicknesses, – it seems very rare.[/quote]

How interesting.

I went on a long hiking trip not long after making this thread, which is why I have not replied until now.

I separated all of the infected B. uropthalmoides and treated them with the typical (at least in the US) formalin/malachite green solution so often used against protozoan parasites. All of them made a complete recovery by the time I left for my hiking trip, and when I returned, there was still no sign whatsoever of the cysts; they were also put into a tank already housing a few Oryzias fry, and none of the fry became infected either.

I wish my microscope was the kind with a camera, but it is not, and it is also very old (manufactured in 1946-48). Even with some of the upgrades I have given it, it cannot compete with a newer scope. The organisms I viewed under the microscope were very similar to “ich” in appearance, and did not have the golden-brown color associated with dinoflagellates. The cysts on the fish were also much smaller than those of ich; so small that at first I thought that I was seeing a piscinoodinium (“velvet”) infection.

The Paros were not infected, although they did not take kindly to the disturbances caused by my attempts to capture the boraras. I have moved the rest of the B. uropthalmoides into a different tank, and I am moving my B brigittae into that tank instead. I also bought some more ketapang leaves before I left and added them to the tank to help restore the correct water conditions.

So far, everyone seems fine. Also, no worries Deepin Peat: I’m fairly new to blackwater fish still (compared to the rest of you), so I appreciate the extra information.

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