White spot on neon tetra--ich or something else?

[bennyblee]

Hi everyone, could use some second opinions on whether my neon tetra has ich or not.

~3 weeks ago, I noticed a white spot on the tetra, and was worried it was ich. My tank had an outbreak several months prior, which I successfully treated with Ich-X. I had not introduced anything new other than an assassin snail, that in my excitement did not think to quarantine.

The next morning was when the spot appeared--which seemed way to fast to be ich that hitchhiked in on the assassin snail, so I wasn't sure what it was. So I just watched the fish closely for a week or so. Every day or two, a new white spot would appear and the previous would go away. He was acting fine the whole time. One spot that had developed, on the tip of the adipose fin, never went away (and is still there now, 3 weeks later--you can see in the photo). My other fish (4 other neon tetras, 4 celestial pearl danios) were acting fine. Finally, I decided to treat when I saw one of the other tetras flash (just one time!) against the substrate. Just that one time, and never again since...

I raised temp to 80F, and treated for 7 days with Ich-X, doing daily 30% PWC as instructed. The only thing I FORGOT to do was switch from Prime to a different conditioner, as they suggest. On the 7th day of treatment, I saw another spot, which I was then convinced couldn't be due to ich, given that the tank was on the 7th day of treatment. That spot resolved and the fish has been fine for the last week, but then today another white spot (see photo below). In between, the only thing different is I had added a new piece of driftwood, some anubias nana, and some christmas moss. The plants had undergone bleach dip followed by 4 weeks of quarantine followed by a second bleach dip and vigorous rinse before adding. The driftwood I didn't bleach but quarantined for 4 weeks.

Is this really ich that only this one tetra appears susceptible to? Is it something else? Did treating the tank with Prime reduce the effectiveness of the Ich-X (which is the theoretical risk), meaning my treatment just wasn't successful? If so, the tank has been dealing with ich for the last month with only this one fish getting a single spot on occasion.

Full details below. Thanks!

1~What type of fish is afflicted? In addition, please describe what is wrong with the fish to the best of your ability (i.e. cotton like growth, bloated, etc.).

See above

2~What are your tank parameters (ammonia, nitrites, nitrates, temp, pH)? Please give exact values.

Ammonia 0, nitrites 0, nitrates 10, temp currently 78 C (I set to 75 but when it gets really hot like it is here now, my house gets warm...), pH 7.8 (has always been at 7.8)

3~ How large is the tank? How long has the tank been set up?

20G high, finished cycling and stocked 5 months ago

4~What type of filtration are you using? Please give the name and number (i.e. Fluval 304) and amount of gph if known.

Marina Slim S20 HOB, filled with sponge material and ceramic biorings, NOT the special filter cartridges. Set to medium flow, plenty of bubbles at the drop-in, not sure what the gph is.

5~How many fish are in the tank? What kinds of fish are they and what are their current sizes?

See above

6~When is the last time you did a water change and vacuum the gravel? How often do you do this? How much water do you remove at a time?

Yesterday. Vacuum and ~40% PWC one weekly, religiously.

7~How long have you had the fish? If the fish is new, how did you acclimate it/them?

From original stocking 5 months ago

8~Have you added anything new to the tank--decor, new dechlorinator, new substrate, etc.?

See above

9~What kind of food have you been feeding your fish, have you changed their diet recently?


Rotation between flakes, omega micro pellets, and frozen brine shrimp, no changes in months

 

[Aiken Drum]

Cant really say from the photo whether its ich or not. I would say from your description and reading through your historical posts its likely to be ich.

If you treated your fish previously as you describe above, then you may not have cleared the ich. As per our previous discussion the speed of the lifecycle of ich is temperature dependant and the medication can only kill ich during its free swimming stage. At typical aquarium temperatures (say 24c) the ich lifecycle takes about a month. At 28c about a week. At your 26c lets say 2 to 3 weeks. So medicating at 26c for 7 days wont treat the tank for a full lifecycle and may not have caught all the ich during their freeswimming stage.

Why only one fish showing symptoms? Otherwise healthy fish can usually live with the ich parasite just fine and show no signs. I would hazard a guess a lot of tanks are infected without anyone ever knowing about it. The parasite goes about its business, going through its lifecycle, and its only when it infects a fish that has a compromised immune system for other reason that symptoms appear.

 

[bennyblee]

Thanks Aiken, sorry I should have clarified. The first time I treated, I treated until all lesions were gone, and then an additional 7 days, so it was close to 2 weeks of treatment total, the final week being when all fish were visibly clear. This time, there actually weren't any visible lesions the day I started to treat, so I planned for 7 days. If the white spot that appeared on day 7 was ich, that would have meant the fish had been infected at least 7 days before but didn't develop the spot until day 7. At that temp, I thought that would have been too long, but you are correct I can say that with any high degree of certainty. I've found a number of sources that say that at 80F it should be no more than a week to complete the entire cycle (not just the tissue phase), but the estimates range all over the place.



If the symptoms are so mild and all fish seem to being just fine otherwise, is it worth re-treating now? I don't have plans to introduce any new fish anytime soon, but would probably treat empirically if/when I do in the future if I hold off for now...

 

[Aiken Drum]

Snails dont carry ich, so thats unlikely to be your source. It could have been a free swimming parasite that was in the water. If you just dumped the snail and water in your tank again thats possibly a route of infection. I suppose any drop of water left on the snail could have a parasite in it, so while unlikely, even if you were careful transferring your snail it could happen that way. I suppose its possible a parasite was attached to the shell also.

2 weeks may not have been long enough at 26c. Touch and go.

Its entirely up to you. If you want to risk that your tank is free of parasites and just retreat if symptoms reoccur thats a valid route depending on how risk averse you are.

You have to take account that the lifecycle isnt all the parasites at the same stage at the same time. There will some freeswimming, some at an infectious stage, some in the substrate reproducing. Thats why you medicate for a complete lifecycle to ensure you get all the parasites no matter at what stage of the lifecycle they were when you start your treatment.