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“Red Slime” or Red Algae

Just like with “Brown Algae”, there are two distinct things people will be searching for when they use the search term “Red Algae” and I will try to satisfy both of those on this one web page.  Red algae as it pertains to aquariums is a common problem among saltwater aquariums.  It typically effects more mature saltwater aquariums unlike “brown algae” problems in an aquarium.  Aquarium “Red Algae” is actually a type of bacteria called cyanobacteria and it is photosynthetic.  Unlike the diatomaceous “brown algae” which isn’t really algae at all, red algae do belong to a much larger group of organisms scientifically classified as “red algae.”  The red algae, or Rhodophyta are one of the oldest groups of algae. Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing.  I will divide this web page into sections related towards the cure for aquarium “red algae” and then sections relating to the scientific Phylum of Rhodophyta.

Aquarium Red Algae

Red Algae – Phylum Rhodophyta

Aquarium Red Algae

Red Algae Cleaners

The more common maroon colored Red Algae
The more common maroon colored Red Algae

“Red Slime” algae or simple “Red Algae” is common problems in saltwater aquariums and does not effect freshwater tanks.

 

 

 

Black Cyanobacteria, a black form of the common Red Algae found in aquariums
Black Cyanobacteria, a black form of the common Red Algae found in aquariums

“Red Slime” algae is actually a type of bacteria called cyanobacteria and it is photosynthetic.  Unlike other types of green filamentatious algae Red Slime algae can actually take hold even when there are very low nitrates in the tank.  To make things more difficult, a lot of invertebrates that will eat green algae will avoid Red Slime algae.  This can make it a difficult problem to address in the aquarium. There is also a black form of cyanobacteria that is sometimes found in tanks that is equally difficult to control.

 

Control Red Algae with Nitrate Elimination
Control Red Algae with Nitrate Elimination

To combat Cyanobacteria, it is helpful to control phosphates and keep phosphates as low as possible as well as nitrates.  Nitrates can be kept low with denitrification such as the Aquaripure nitrate reactor but phosphates will also need to be controlled with a phosphate remover that will need to be replaced monthly.

 

 

Seachem PhosGuard 1 Liter Aquarium Filter Media

Seachem PhosGuard 1 Liter Aquarium Filter Media

  • For marine and freshwater aquarium filters
  • Rapidly hydrodynamics
  • Removes phosphate
  • Phosguard rapidly removes phosphate and silicate from marine and freshwater aquaria. It is not recommended for phosphate buffered freshwater. Phosguard is highly porous for high capacity and bead-shaped for optimum water flow. It outperforms all competing products.

Trying to physically eliminate it by sucking it out with a tube during a water change will help control it.  Even though most invertebrates do not prefer to eat it, hermit crabs will do so if they are hungry enough so a hermit crab per gallon or two of water will typically eliminate the problem.

Cyanobacteria is probably the most difficult of all aquarium algae to prevent and control because it can actually take hold and grow even in water with no nitrates.  However, controlling phosphates and plenty of invertebrates will typically control it.  However, if it does take hold in an aquarium it is actually fairly easy to eliminate.  As cyanobacteria is really just single celled bacteria, it can be killed with antibiotics designed to kill it.  Antibiotics designed to kill cyanobacteria can interfere with a denitrator / nitrate reactor.  Fortunately, the antibiotics will act quickly to eliminate the cyanobacteria and then carbon can be used to eliminate the antibiotics from the tank.  With an Aquaripure denitrator, the nitrate reactor can safely be turned off up to four days while this process is completed.  There are currently no antibiotics designed to kill the red algae on Amazon at this time but there are several other products designed to inhibit it more naturally which should not interfere with denitrification at all.  It seems they all need very good water circulation and aeration in the tank.

Red Algae Cleaners

KZ Korallen-Zucht - Cyano Clean Red Algae inhibitor
KZ Korallen-Zucht – Cyano Clean Red Algae inhibitor

KZ Korallen-Zucht – Cyano Clean Red Algae inhibitor

  • Formulated with nutrient-scavenging bacterial strains that diminish Cyanobacteria’s food source
  • Reef-safe and does not alter nutrient composition of tank
  • Dose weekly for preventative measure
  • Contains no antibiotics
  • Will not affect biological filtration
CHEMI-CLEAN RED ALGAE SLIME REMOVER -
CHEMI-CLEAN RED ALGAE SLIME REMOVER

CHEMI-CLEAN RED ALGAE SLIME REMOVER –
BOYD ENTERPRISES INC

Removes red, black, blue-green, and methane (bubble) producing algae from marine aquariums
Completely safe for use in all reef tanks invertebrates desirable macro algae nitrifying bacteria and fish
Works within 48 hours oxidizing trapped organic sludge and promotes an ideal enzyme balance
Chemiclean will clean stains from red cyanobacteria in aquariums

Kent Marine Poly Ox Red Algae Slime Remover
Kent Marine Poly Ox Red Algae Slime Remover

Kent Marine Poly Ox Red Algae Slime Remover

  • Organic material oxidizer
  • Does not contain any algaecide
  • Assists in preventing growth of various cyanobacteria
  • Safe to use in both freshwater and marine aquariums
  • Not for human consumption

 

 

Another preventative measure is UV sterilization.  A UV sterilizer will simply kill any red algae that might cause it to spread in the tank.  Unfortunately, they will also kill other beneficial microorganism in the tank such as rotifers and copepods.  A UV sterilizer will not act as a nitrate and nutrient “sponge” in the system.  However, it can help control red algae, other algae issues and even fish disease.  Here is the link to the Aquarium UV Sterilizer page here if you wish to look at UV further.

We believe that using microfauna, invertebrates and denitrification is preferable as a primary control.  However, if a UV sterilizer is used continuously to address cloudy water, other algae issues, or fish disease then microfauna can be added after the initial problem has cleared up and then only used briefly (a few hours at a time or maybe an hour a day on a timer) and intermittently to help “polish” the tank up as needed and be kept as a back up solution should it become necessary (such as a new outbreak.)  Click here to visit the Aquarium Microfauna webpage where you can purchase microfauna.

Once under control, a good clean up crew will help keep it from becoming a problem again.  You will need to replenish your clean up crew regularly as critters die and the cleaners cease to be as effective as they once were.

Live Marine Inverts red ALGAE Cleaner Crew Mix 25 assorted Snails and blue legs 2 emerlad crabs and 1 pink urchin, 2 peppermint shrimp
Live Marine Inverts red ALGAE Cleaner Crew Mix 25 assorted Snails and blue legs 2 emerlad crabs and 1 pink urchin, 2 peppermint shrimp

Assortment of blue leg hermits, star snails, chestnuts, orange snail, narite and nassarius.  Although the picture does not show live animals this is supposed to be a live package.

 

 

Red Algae – Phylum Rhodophyta

Red Algae Habitat

Red Algae Taxonomy

Red Algae Morphology

Red Algae Reproduction

Red Algae Evolution

Red Algae Photos

The red algae, or Rhodophyta (/roʊˈdɒfɪtə/ roh-DOF-fit-tə or /ˌroʊdəˈfaɪtə/ ROH-də-FY-tə; from Ancient Greek: ῥόδον rhodon, “rose” and φυτόν phyton, “plant”), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are found in the Florideophyceae (class), and consist of mostly multicellular, marine algae, including many notable seaweeds. Approximately 5% of the red algae occur in freshwater environments with greater concentrations found in the warmer area.

Palmaria palmata, dulse red algae
Palmaria palmata, dulse red algae

The red algae form a distinct group characterized by having eukaryotic cells without flagella and centrioles, chloroplasts that lack external endoplasmic reticulum and contain unstacked (stoma) thylakoids, and use phycobiliproteins as accessory pigments, which give them their red color. Red algae store sugars as floridean starch, which is a type of starch that consists of highly branched amylopectin without amylose, as food reserves outside their plastids. Most red algae are also multicellular, macroscopic, marine, and reproduce sexually. The red algal life history is typically an alternation of generations that may have three generations rather than two.

Chloroplasts evolved following an endosymbiotic event between an ancestral, photosynthetic cyanobacterium and an early eukarytoic Phagotroph. This event (termed Primary endosymbiosis) resulted in the origin of the red and Green algae, and the Glaucophytes, which make up the oldest evolutionary lineages of photosynthetic eukaryotes. A secondary endosymbiosis event involving an ancestral red alga and a heterotrophic eukaryote resulted in the evolution and diversification of several other photosynthetic lineages.

The coralline algae, which secrete calcium carbonate and play a major role in building coral reefs, belong here. Red algae such as dulse (Palmaria palmata) and laver (nori/gim) are a traditional part of European and Asian cuisines and are used to make other products such as agar, carrageenans and other food additives.

Red Algae Habitat

Cladostephus spongiosus red algae
Cladostephus spongiosus red algae

Unicellular members of the Cyanidiophyceae are thermoacidophiles and are found in sulphuric hot springs and other acidic environments. The remaining taxa are found in marine and freshwater environments. Most rhodophytes are marine with a worldwide distribution, and are often found at greater depths compared to other seaweeds because of dominance in certain pigments (i.e., Phycoerythrin) within their chloroplasts. Some marine species are found on sandy shores, while most others can be found attached to rocky substrata. Freshwater species account for 5% of red algae diversity, but they also have a worldwide distribution in various habitats; they generally prefer clean, high-flow streams with clear waters and rocky bottoms, but with some exceptions. Both marine and freshwater taxa are represented by free-living macroalgal forms and smaller endo/epiphytic/zoic forms, meaning they live in or on other algae, plants, and animals. In addition, some marine species have adopted a parasitic lifestyle and may be found on closely or more distantly related red algal hosts.

Red Algae Taxonomy

Chondrus crispus, Irish moss red algae
Chondrus crispus, Irish moss red algae

In the system of Adl et al. 2005, the red algae are classified in the Archaeplastida, along with the glaucophytes and green algae plus land plants (Viridiplantae or Chloroplastida). The authors use a hierarchical arrangement where the clade names do not signify rank; the class name Rhodophyceae is used for the red algae. No subdivisions are given; the authors say, “Traditional subgroups are artificial constructs, and no longer valid.”

Below are other published taxonomies of the red algae using molecular and traditional alpha taxonomic data; however, the taxonomy of the red algae is still in a state of flux (with classification above the level of order having received little scientific attention for most of the 20th century).

  • If one defines the kingdom Plantae to mean the Archaeplastida, the red algae will be part of that kingdom
  • If Plantae are defined more narrowly, to be the Viridiplantae, then the red algae might be considered their own kingdom, or part of the kingdom Protista.

A major research initiative to reconstruct the Red Algal Tree of Life (RedToL) using phylogenetic and genomic approaches is funded by the National Science Foundation as part of the Assembling the Tree of Life Program.

Red Algae Morphology

Red algae have double cell walls. The outer layers contain the polysaccharides agarose and agaropectin that can be extracted from the cell walls by boiling as agar. The internal walls are mostly cellulose.

Chondrus crispus, Irish moss red algae
Chondrus crispus, Irish moss red algae

Pit connections and pit plugs are unique and distinctive features of red algae that form during the process of cytokinesis following mitosis. In red algae, cytokinesis is incomplete. Typically, a small pore is left in the middle of the newly formed partition. The pit connection is formed where the daughter cells remain in contact.

Shortly after the pit connection is formed, cytoplasmic continuity is blocked by the generation of a pit plug, which is deposited in the wall gap that connects the cells.

Connections between cells having a common parent cell are called primary pit connections. Because apical growth is the norm in red algae, most cells have two primary pit connections, one to each adjacent cell.

Connections that exist between cells not sharing a common parent cell are labeled secondary pit connections. These connections are formed when an unequal cell division produced a nucleated daughter cell that then fuses to an adjacent cell. Patterns of secondary pit connections can be seen in the order Ceramiales.

Schmitzia hiscockiana red algae
Schmitzia hiscockiana red algae

After a pit connection is formed, tubular membranes appear. A granular protein, called the plug core, then forms around the membranes. The tubular membranes eventually disappear. While some orders of red algae simply have a plug core, others have an associated membrane at each side of the protein mass, called cap membranes. The pit plug continues to exist between the cells until one of the cells dies. When this happens, the living cell produces a layer of wall material that seals off the plug.

The pit connections have been suggested to function as structural reinforcement, or as avenues for cell-to-cell communication and transport in red algae, however little data supports this hypothesis.

Red Algae Reproduction

The reproductive cycle of red algae may be triggered by factors such as day length.

Red algae lack motile sperm. Hence, they rely on water currents to transport their gametes to the female organs – although their sperm are capable of “gliding” to a carpogonium’s trichogyne.

The trichogyne will continue to grow until it encounters a spermatium; once it has been fertilized, the cell wall at its base progressively thickens, separating it from the rest of the carpogonium at its base.

Upon their collision, the walls of the spermatium and carpogonium dissolve. The male nucleus divides and moves into the carpogonium; one half of the nucleus merges with the carpogonium’s nucleus.

"Slime" Aquarium Red Algae
“Slime” Aquarium Red Algae

Red algae are red due to phycoerythrin. They contain the sulfated polysaccharide carrageenan in the amorphous sections of their cell walls, although red algae from the genus Porphyra contain porphyran. They also produce a specific type of tannin called phlorotannins, but in lower amount than brown algae do.

Red Algae Evolution

One of the oldest fossils identified as a red alga is also the oldest fossil eukaryote that belongs to a specific modern taxon. Bangiomorpha pubescens, a multicellular fossil from arctic Canada, strongly resembles the modern red alga Bangia despite occurring in rocks dating to 1.2 billion years ago.

Two kinds of fossils resembling red algae were found sometime between 2006 and 2011 in well-preserved sedimentary rocks in Chitrakoot, central India. The presumed red algae lie embedded in fossil mats of cyanobacteria, called stromatolites, in 1.6 billion-year-old Indian phosphorite — making them the oldest plant-like fossils ever found by about 400 million years.

Coraline Red Algae
Coraline Red Algae

Red algae are important builders of limestone reefs. The earliest such coralline algae, the solenopores, are known from the Cambrian period. Other algae of different origins filled a similar role in the late Paleozoic, and in more recent reefs.

Calcite crusts that have been interpreted as the remains of coralline red algae, date to the terminal Proterozoic. Thallophytes resembling coralline red algae are known from the late Proterozoic Doushantuo formation.

Chromista and Alveolata algae (e.g., chrysophytes, diatoms, phaeophytes, dinophytes) seem to have evolved from bikonts that have acquired red algae as endosymbionts. According to this theory, over time these endosymbiont red algae have evolved to become chloroplasts. This part of endosymbiotic theory is supported by various structural and genetic similarities.

Over 7,000 species are currently described for the red algae, but the taxonomy is in constant flux with new species described each year. The vast majority of these are marine with about 200 that live only in fresh water.

Red Algae Photos

Some examples of species and genera of red algae are:

Atractophora hypnoides red algae
Atractophora hypnoides red algae

 

 

 

 

 

 

Schmitzia hiscockiana red algae
Schmitzia hiscockiana red algae

 

 

 

 

 

 

Palmaria palmata, dulse red algae
Palmaria palmata, dulse red algae

 

 

 

 

 

Cladostephus spongiosus red algae
Cladostephus spongiosus red algae

 

 

 

 

 

Chondrus crispus, Irish moss red algae
Chondrus crispus, Irish moss red algae

 

 

 

 

 

 

Chondrus crispus, Irish moss red algae
Chondrus crispus, Irish moss red algae

 

 

 

 

 

 

 

"Slime" Aquarium Red Algae
“Slime” Aquarium Red Algae

 

 

 

 

 

Coraline Red Algae
Coraline Red Algae