Guppy With Clamped Tail

[Distance_Time]

Hi all, relatively new to the hobby here. I have a 55G planted tank setup that has been running without issue for maybe 4-5 months now. Originally started with plants, then added nerite snails and amano shrimp. I also have a few pieces of driftwood in there, in case that's relevant... Anyways, the tank is well-cycled.

A couples weeks ago I added 10 guppies (4 male, 6 female). This morning I noticed one of the females with what appears to be "clamped fin". She's lost some coloring and clearly struggling, although she will still swim around a bit. All other fish are looking fine and active. No issues spotted with the shrimp either, for what it's worth.

I did about a 30% water change right away (used dechlorinator), as I noticed low levels of ammonia in my water parameters (~0.25ppm). Everything else was in a low/normal range. Water temp is 78 degrees F. PH around 7.4. Have a cannister filter running with no obvious signs of problems, although haven't specifically cleaned it in some time. Feeding once per day on average, although I was away for 3 days over the weekend so they went without food during that span.

Any ideas/recommendations as to what the best course of action would be greatly appreciated. Thanks!

 

[Colin_T]

Hi and welcome to the forum

Clamped fins can be caused by poor water quality (ammonia, nitrite, nitrate), or an external bacterial or protozoan infection. In this case it's probably protozoan due to the guppies being new.

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Wipe the inside of the glass down with a clean fish sponge. This removes the biofilm on the glass and the biofilm will contain lots of harmful bacteria, fungus, protozoans and various other microscopic life forms.

Do a 75% water change and gravel clean the substrate. The water change and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in. It also removes a lot of the gunk and this means any medication can work on treating the fish instead of being wasted killing the pathogens in the gunk.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use the media. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens.

Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.

Add some salt, (see directions below).

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SALT
You can add rock salt (often sold as aquarium salt) or swimming pool salt to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, Bettas & gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria, fish, plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.

When you first add salt, add the salt to a small bucket of tank water and dissolve the salt. Then slowly pour the salt water into the tank near the filter outlet. Add the salt over a couple of minutes.

 

[Distance_Time]

Thanks for taking the time to reply! Much appreciated advice! I'll get start on that right away.