White molly getting thinner

[Aniket]

I brought one white bigger molly. She was looking bigger than rest mollies and today i saw she looks getting thinner her eye sight looks like hammer head shark (not that much). I changed 50% water and added methylene blue. What could be the cause of this transformation and what should I do?

 

[Colin_T]

If you can post a picture of the fish it helps with identifying a problem.

How long have you had the fish for?

Have you tested the water for ammonia, nitrite, nitrate, general hardness (GH) & pH?

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Methylene Blue will kill filter bacteria so monitor the ammonia levels over the next few weeks.

 

[Aniket]

If you can post a picture of the fish it helps with identifying a problem.

How long have you had the fish for?

Have you tested the water for ammonia, nitrite, nitrate, general hardness (GH) & pH?

-------------------------
Methylene Blue will kill filter bacteria so monitor the ammonia levels over the next few weeks.

Pic is not that clear because she moves everytime

 

[Colin_T]

The pictures are blury because there is not enough light. Cameras need lots of light to be able to focus on things and if the object is moving, they need more light. Make sure the light is on the aquarium. Have the room light on and curtains open. Use the flash on the camera and that usually makes a big difference.

If the fish was fat one day and skinny the next day she might have given birth and the babies are in the tank or got eaten.

Livebearers (mollies, guppies, swordtails & platies) regularly carry gill flukes and intestinal worms and these can make the fish lose condition and become skinny over a period of time (a month or more).
You can treat tapeworm and gill flukes with Praziquantel. Round or thread worms can be treated with Levamisole.

The bulging eyes can be poor water quality or a bacterial infection. If the general hardness (GH) is below 250ppm and the pH is below 7.0, the mollies will be having a hard time and increasing the GH will help. You can check your water supply company's website or call them and ask them what the GH and pH is. Or you can take a sample of your tank water to the local pet shop and ask them to test it for you. Write the results (in numbers) down when they do the test.

If the water is good and there is no ammonia or nitrite, and the nitrate is less than 20ppm, and the GH is above 250ppm and pH above 7.0, the fish could have a bacterial infection that is causing the eyes to bulge out a bit. Methylene Blue is usually sufficient to treat this.

However, before adding any more medication, check the water first. Soft water and ammonia or nitrite will cause these problems to mollies. Doing a 75% water change and gravel cleaning the substrate each day for a week, and making sure the GH & pH are suitable, will normally fix most problems. You can treat all your fish for worms and gill flukes and that should help too.