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Red Slime Algae (Cyanobacteria)

Red Slime Algae Causes and Cures


Red Slime Algae (Cyanobacteria)

Left-Handed Hermit Crab

Photo by Keoki Stender
Allowing excess DOCs to accumulate in an aquarium in turn gives rise to nitrate (NO3) problems. However, nitrates can also be introduced in the same manner as phosphates, and because it is the final byproduct produced in the nitrogen cycling process, it can naturally build to high levels due the lack of proper aquarium maintenance care. Another contributor to DOC/nitrate problems is when new live rock is introduced, as the curing process can add nutrients when some organisms on the rock dies off.
  • Solutions: Practice good aquarium maintenance care routines! This includes keeping the substrate clean, cutting back on feedings, regularly rinsing, rejuvenating or changing any type of filtering or adsorbing materials (such as filter flosses, cartridges, bio wheels, sponges and carbon), performing regular partial water changes, and for DOCs in particular, adding a protein skimmer (read reviews & compare prices). For those with systems that have been running for some time and use wet/dry trickle type filters, the bio media in them, especially bio balls, are real nitrate factories, and therefore should be carefully rinsed and cleaned periodically.
  • While most hermit crab and snails won't eat this type of algae, the Left-Handed or Dwarf Zebra Hermit Crab has been known to peck away at it in an aquarium. To help keep the aquarium bottom clean and tidy add some tank friendly algae/detritus eating hermit crabs, one or two true crabs, shrimps, or other good substrate sifting tank janitors, or a fish. Scott Michael recommends the Orange-Spotted Sleeper Goby (Valenciennia puellaris) as being the best.
  • When adding live rock, take the time to cure it properly.
  • Important Note: If your tank is still cycling, DO NOT add any new animals, do ANY water changes, or perform ANY MAJOR substrate or filter cleaning tasks, other than to change dirty pre-filtering materials and/or to QUICK siphon stuff off the bottom, until the tank has COMPLETELY FINISHED cycling. Because this type of algae does not attach well, it can easily be peeled off and removed by light siphoning, with larger floating pieces being removed with a net, or turkey baster.
While cleaning up the tank and following proper maintenance care routines won't give immediate results, you can use one of a number of additives which you can find in Top Red Slime Algae Removers to cure the problem quickly (within a day or 2). However, many of these types of treatments appear to only solve the symptom (the slime algae), not the underlying problem(s). Cyanobacteria are a form of bacteria, and many of the additives currently in use are antibiotics, which are medications that can weaken or totally wipe out the biological filter base of an aquarium. Use these types of treatments cautiously!

By putting into action any of these solutions, as the growth sources are being eliminated you should see a gradual decrease in the growth of the slime algae. In the meantime, while you determine and correct the actual cause underlying the problem, the unsightly algae can manually be removed as mentioned above.

One final interesting note is that because slime algae consume nitrates, often when aquarists perform nitrate tests, the readings come up as normal. Don't be deceived. If you were to remove the algae temporarily before putting into action any of the above solutions, in all likelihood you will see a rise in the nitrate levels in the aquarium. It's like a Catch 22. The nitrates have actually been there all along, but unreadable as the algae is feeding on it, therefore the nitrates appear to be in check. This applies to many other forms of algae as well!

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