Seem to be losing all my molly fish :(

[Colin_T]

75% water change has just been done, whole tank has been scrubbed down with a brand new sponge. Filter has had a complete clean just now too for the new water. I've added your recommended dose of aquarium salt just now until the treatment arrives (eSHa 2000, eSHa Exit). Thank you for your advice. I will be keeping the thread updated.

Did you throw you old filter sponges away?
If yes, get them back into the filter or you will have ammonia and nitrite problems.

Filter media/ materials should only be replaced if they are falling apart or don't belong in a filter (carbon & zeolite). Sponges last for years and should be squeezed out in a bucket of tank water and the sponge re-used. The bucket of dirty water gets poured on the lawn outside.

The filter media, including sponges, hold beneficial bacteria that keep the ammonia and nitrite levels at 0ppm. If you replace the sponge with a new sponge, you get rid of the good bacteria and the tank will have to cycle again. Cycling is where the beneficial filter bacteria grow to a suitable sized colony to keep the water clean. This normally takes around 4-6 weeks.

You need to put the old sponge back in the filter and monitor the ammonia and nitrite levels for the next few weeks. If you get an ammonia or nitrite reading above 0ppm, or a nitrate reading above 20ppm, do a 75% water change every day until the levels are 0ppm.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

 

[mollydesperation]

If yes, get them back into the filter or you will have ammonia and nitrite problems.

Nope, just gave them a scrub!

 

[mollydesperation]

Fuplie, I didn't realise it was a planted substrate. No, don't add that! It'll leach ammonia and nitrogen, that's the last thing we need.

Needs to be inert. Sand or gravel. Even if you only use a thin layer of it for now, then change it out once the fish recover and can handle you changing the substrate again.

Only stuff i've got at the moment. Best to go without at all? Just grab some save tomorrow to sort this out? then go to the substrate once if everything is sorted for platns?

 

[Essjay]

You don't actually need plant substrates; plain sand is fine with root tablet fertiliser for root feeding plants. Stem plants usually feed through their leaves so need a liquid fertiliser.
Look for Argos play sand, cheap and does the job perfectly. Make sure you rinse it before putting it in the tank as it will have a lot of dust. Put some in a bucket, run cold water in and swoosh it all round then pour off the dusty water. Rinse again and again until the water is more or less clear, then put the washed sand aside and do another batch.

 

[mollydesperation]

Look for Argos play sand, cheap and does the job perfectly. Make sure you rinse it before putting it in the tank as it will have a lot of dust. Put some in a bucket, run cold water in and swoosh it all round then pour off the dusty water. Rinse again and again until the water is more or less clear, then put the washed sand aside and do another batch.

Lovely thank you. Will get ahold of some in the morning.