• Skip to main content
  • Skip to primary sidebar
  • Home
  • Bettas 101
    • Acclimation
    • All About Water
      • Nitrogen Cycle
      • Ph & Ammonia
      • Water Changes
    • Betta Fish Anatomy
    • Betta Vases
    • Choosing a Tank
    • Feeding Bettas
      • Food Myths
      • Frozen & Live Betta Food
    • Tankmates for Bettas
      • African Dwarf Frogs & Bettas
      • Apple Snails & Bettas
      • Neon Tetras & Bettas
      • Otocinclus Catfish & Bettas
      • Quarantine New Fish
    • Plakat Betta
    • Rosetail Betta
    • Veil-tail Betta
  • Sick Betta
    • Diseases and Treatment
    • Aging Bettas
    • Bloating and Constipation
    • Cotton Wool Disease
    • Dropsy
    • Fin Rot and Fin Loss
    • First Steps
    • Gill Hyperplasia
    • Ich
    • Popeye
    • Septicemia (Infection)
    • Swim Bladder Disorder
    • Sick Betta Symptom Checker
    • Velvet Disease
    • Wounded Betta
    • Fish Tank Granuloma
  • Behavior
    • Bubble Nests
    • Skittish Bettas
    • Tail Biting
  • Breeding Bettas
  • Equipment
  • Q & A
  • Other fish
  • Contact

Fish Care

Everything You Need to Know About Betta Fish

You are here: Home / Equipment / Glossary: Detritus (Mulm)

Glossary: Detritus (Mulm)


Dirty Tank (which has been cleaned!!!), originally uploaded by blaqphlegm.

In the aquarium, detritus (often called mulm) is organic material made up of fragments of fish waste, uneaten food particles, dead animals, mucus, shed skin and decaying plant matter. It is commonly suspended in the water and sucked into the filter but in conditions where there is little water movement, like Betta bowls, it can settle to the bottom and pile up into a fluffy brown or gray carpet. It can also be sticky or slick and may coat plants and decor. In a cycled aquarium this dead material is not dangerous in and of itself, but being high in nutrients it can lead to a rise in nitrate levels and algae growth. If not removed in an uncycled aquarium it will breakdown further into harmful ammonia. This toxin poses an imminent threat to fish and can lead to disease or even death. While ammonia is a major concern, the detritus itself generally isn’t and is just simply removed upon detection.

If you find detritus in your tank the easiest method for removal is by running a siphon a half inch or so over the tank bottom. Detritus is very light and is sucked up easily. In smaller Betta bowls, a simple turkey baster will remove the material. If detritus is a reoccurring issue in your tank you may want to consider installing a filter.


Filed Under: Equipment, Nitrogen Cycle, Siphon, Water Quality

Reader Interactions

Comments

  1. Bella476 says:

    Thank you so much for posting this! My betta is my life and I was so worried when the little white thingies on the top of his water. I have been treating with bacteria stuff but I didn’t know if it was doing anything. Thank you so much for clarifying this issue for me! -Bella

    Reply
  2. Esteban says:

    I drop a comment whenever I like a article on a website or I have something to add to the discussion.
    It’s caused by the sincerness communicated in the article
    I browsed. And after this article Glossary:
    Detritus (Mulm) | Betta Fish Care. I was moved enough to
    leave a commenta response 😛 I do have a few questions for you if it’s okay.
    Could it be just me or do some of these responses appear as if they are left by brain dead visitors?
    😛 And, if you are writing at additional sites, I’d like to
    keep up with anything new you have to post. Would you list every one of all
    your social sites like your Facebook page, twitter feed, or linkedin profile?

    Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Primary Sidebar

Search


Recent Posts

  • Cool Betta Fish Tank Ideas
  • How Long Do Betta Fish Live For? – 5 Helpful Tips For a Long and Happy Life
  • 3 Gallon Fish Tank for Betta
  • 10 Gallon Aquarium Stands and Cabinets
  • How Much Do Betta Fish Cost to Buy and Care For?

NippyFish Facebook Page

Visit the NippyFish Facebook Page

Featured Posts

Complete Guide to Betta Fish Diseases and Treatment

This complete guide on Betta fish illnesses and diseases from A-Z will help you pinpoint what is wrong with your Betta and how to treat it.

The 4 Most Common Signs of Illness in Betta Fish

This article focuses on the 4 most common signs of illness in Betta fish.

Betta Fish Tank Setup – A Detailed Guide For Beginners

This article will be providing a detailed beginners guide on how to setup a tank for your Betta fish.

Top 12 Betta Fish Toys

This article has a list of some of our favorite Betta fish toys. Don’t have a bored Betta.

Setup an Aquatic Plant Environment For Your Betta

Having a healthy plant in your tank will help to improve the water quality by filtering out waste and removing some of the CO2 that’s produced by your fish.

Copyright © 2025 All Rights Reserved | NippyFish | Privacy Policy

Nippyfish.net is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com.