How much mulm is too much mulm?

[TGOATW]

I've read that mulm is harmless and even benefcial to your fish tank, but i've also read somewhere that if you have a gravel substrate and can see mulm above it, it means theres a lot of it.
Should i remove it? Or should i keep it for the shrimps to sift through?

 

[GaryE]

I don't know the story for shrimp only tanks, but I know with fish accumulated mulm can be a problem as it can provide a home and breeding ground for parasites that, in sufficient numbers, can then attack the fish. A lot of my fish are detritivores, eaters of mulm, but I can't really offer them that option in the closed system of a tank, In the wild, the water keeps flowing and the mulm has a different effect on the water, but trapped in a tank, it isn't a good thing when there's a lot of it.

 

[AJ356]

I've always wondered about this. Especially my fry tanks. I'll often squeeze a mature filter sponge directly into the tank water, meaning there will be a ton of mulm for ages unless I do a major clean up.

 

[TGOATW]

I don't know the story for shrimp only tanks, but I know with fish accumulated mulm can be a problem as it can provide a home and breeding ground for parasites that, in sufficient numbers, can then attack the fish. A lot of my fish are detritivores, eaters of mulm, but I can't really offer them that option in the closed system of a tank, In the wild, the water keeps flowing and the mulm has a different effect on the water, but trapped in a tank, it isn't a good thing when there's a lot of it.

I have ghost shrimps, zebra danios and a hillstream loach. plus some bladder snails.
If it's like that then i should keep mulm to a minimum. Thanks!

 

[GaryE]

This is very unscientific as a sampling, but with killies, tanks where mulm and plant debris gather often have issues with Oodinium spp. (velevet disease) I assume the parasites flare up after living in undetectable populations longterm - they aren't like Ich where you need to introduce them. Excessive mulm may also feed epistylis outbreaks.

I siphon mulm out as I see it. I used to leave it behind when I did water changes, but since I started aiming for it, I've had no Oodinium, and hope it's no longer surviving anywhere in my tanks. That's probably hubris, and by saying it I'll start the magic rolling and see it again tomorrow!

 

[TGOATW]

This is very unscientific as a sampling, but with killies, tanks where mulm and plant debris gather often have issues with Oodinium spp. (velevet disease) I assume the parasites flare up after living in undetectable populations longterm - they aren't like Ich where you need to introduce them. Excessive mulm may also feed epistylis outbreaks.

I siphon mulm out as I see it. I used to leave it behind when I did water changes, but since I started aiming for it, I've had no Oodinium, and hope it's no longer surviving anywhere in my tanks. That's probably hubris, and by saying it I'll start the magic rolling and see it again tomorrow!

I seriously hope nobody have to live through such a nightmare. After learnibg that, i am definetely gonna keep mulm to a minimum. Thanks for the info!

 

[Magnum Man]

I have tanks with what I consider too much mulm , and never had velvet ( knock on wood )

a funny thing, is most of my tanks have no mulm, but tanks that have had "melt downs" in the past got it, and in most it doesn't go away completely afterwards, ( it doesn't help with sand bottom tanks, which makes it harder to suck it out in water changes ) my 10 gallon tanks, were used for other things, before the shrimp, and all had mulm... the couple years of prolific cherry shrimp, have that tank mulm free, but the other colored shrimp tanks still have mulm in them, even a year later, but those 3 tanks have smaller shrimp populations... most of my bigger tanks are mulm free, without me having to do anything, but my 55 gallon tank that had barbs in it previously, that had a melt down, is full of it... it has a jungle of thriving plants, and a sand bottom, so I'm unsure of how to completely free that tank if it, other than I've begun adding cherry shrimp to that tank, and I'm beginning to see clean white spots on the white sand bottom... so to transition that tank naturally, looks like it's going to take some time...

 

[Colin_T]

As Gary said, the more gunk in the tank, the more chance of disease outbreaks, especially protozoan parasites that love gunk. The more common disease outbreaks in tanks with lots of rotting gunk (fish waste and uneaten rotting food) are Costia, Chilodonella and Trichodina. All three are protozoan parasites that can kill fish quickly and they live in small numbers until you miss a water change or gravel clean, then the fish get sick and die.

In my opinion, the less gunk floating around a tank, or sitting on or in the substrate, or in the filter, the better it is for the fish and other inhabitants (snails, shrimp).

 

[TGOATW]

As Gary said, the more gunk in the tank, the more chance of disease outbreaks, especially protozoan parasites that love gunk. The more common disease outbreaks in tanks with lots of rotting gunk (fish waste and uneaten rotting food) are Costia, Chilodonella and Trichodina. All three are protozoan parasites that can kill fish quickly and they live in small numbers until you miss a water change or gravel clean, then the fish get sick and die.

In my opinion, the less gunk floating around a tank, or sitting on or in the substrate, or in the filter, the better it is for the fish and other inhabitants (snails, shrimp).

Makes sense. I first thought it'd be better for the shrimps and plants, but it'd be safer to just remove it after hearing all the advice. Thanks for the confirmation!