Guppy fish mouth open

[Sierkfam3]

Hi! First time poster here. I’m new to the fish world. I have 3 tanks, a 20 gallon, 10 gallon and 3 gallon hospital tank. My female guppy “Big Mama” lives in my 20 gallon tank with 2 males and 5 other females. She’s lived there for 6 months. She’s had 4 batches of Frye. She’s my biggest guppy. Yesterday she appeared perfectly normal. When I checked on her this morning she wasn’t moving and her mouth appears stuck open. I immediately moved her to the hospital tank where she could be alone, but within an hour she was dead. Attached are photos. My water level was checked 3 days ago and perfectly normal. I introduced two new fish female guppies 3 days ago (one of them was found dead yesterday). She is pregnant but appeared more bloated today than normal. Very buoyant, just bobbing at the top of the tank.

 

[Colin_T]

Hi and welcome to the forum

Assuming there is no ammonia or nitrite in the water, the fish probably has a bacterial infection, which would have been introduced with the new guppies.

You can try using salt or anti-biotics.

Before you treat the tank with medication, work out the volume of water in the tank:
measure length x width x height in cm.
divide by 1000.
= volume in litres.
When you measure the height, measure from the top of the substrate to the top of the water level.

There is a calculator/ converter in the "How To Tips" at the top of this page that will let you convert litres to gallons if you need it.

Remove carbon from the filter before treating or it will adsorb the medication and stop it working.

Wipe the inside of the glass down with a clean fish sponge. Do a 75% water change and gravel clean the substrate. 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.

Increase surface turbulence/ aeration when using medications because they reduce the dissolved oxygen in the water.

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You can add rock salt (often sold as aquarium salt), sea 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.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you can double that dose rate, so you would add 2 heaped tablespoons per 20 litres and if there is no improvement after 48 hours, then increase it so there is a total of 4 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, 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 but the higher dose rate will affect some plants. The lower dose rate will not affect plants.

After you use salt and the fish have recovered, you do a 10% water change each day for a week. Then do a 20% water change each day for a week. Then you can do bigger water changes after that.