Introduction to the Saltwater Aquarium Hobby

It dawned on me that I never really introduced the hobby, or why anyone should consider keeping saltwater aquariums as a hobby.  My introduction to the blog explained how I got involved, but I never discussed why anyone else should.  For many, it’s a way to have a “piece of paradise” in colder weather, others bought because their kids watched “Finding Nemo”, while still others view it as a challenging hobby that will never get dull.

Mated pair of High-Fin Gobies with their Pistol Shrimp (symbiotic relationship)

What is a Saltwater Aquarium?
A saltwater aquarium is any aquarium that simulates an ocean environment.  There are coldwater tanks, aggressive fish tanks, jellyfish tanks, and then the typical “mixed reef” of warm-water inhabitants from across the globe.  There are three main categories of aquariums:  the fish only (FO), the fish only with live rock (FOWLR), and the coral reef.


What are the benefits to having an aquarium?
Studies have shown that having an aquarium can lower blood pressure, increase the longevity after a heart attack, decrease muscle tension, and have even been shown to increase the nutritional intake of Alzheimer’s patients.  Other than the physical effects, aquariums can teach children about various creatures and get them excited about science all while encouraging responsible behavior with the environment.

What are the main components of an aquarium?
The obvious are an aquarium tank (made of acrylic or glass usually) and a stand.  Lighting needs depend on the aquarium inhabitants.  Fish-only aquariums are fine with normal flourescents (NO).  Compact flourescents are for FO, FOWLR, and some corals.  T-5 lights are great for FO, FOWLR, and most corals when sized appropriately for the aquarium.  Metal halides are for FO, FOWLR, and most corals when size appropriately; however, the power usage is quite high.  LED’s and other lighting types are used in the hobby, but less than the previous mentioned lights.  Their capabilities are highly dependent.

Filters fall into three main categories:  mechanical (skimming, plastic sponges, and live rock), chemical (carbon, granular ferric oxide (GFO), Zeovit, etc.), and biological (natural sponges, bacteria, and filter-feeders.)  Flow needs in the aquarium depends on the inhabitants.  Sea horses need extremely low flow while small-polyp stoney corals usually need very high flow. 

Some small aquariums have almost everything needed included

What is a coral?
Corals are tiny animals that build skeletons from calcium and other minerals.  The coral polyp is a living animal that consists of a mouth, stomach, and tentacles.  The “corallite” is the calcium shell.  Most corals have a symbiotic relationship with a photosynthetic algae called “zooxanthallae”.  The coral provides protection to the algae while the algae provides the sugars the coral needs to live.

This non-photosynthetic coral does not contain zooxanthallae, so it has tentacles extended to capture food.

Types of corals:
Corals fall into two main groups:  the hard and soft corals.  Soft corals (Alcyonacea) do not build reefs.  They do not build true skeletons.  Instead, they have calcium particle skeletons called “sclerites”.  They’re generally tolerant of poor water conditions, but they can emit highly toxic substances that can harm other corals and even humans.

Soft coral (although this Tubipora sp grows pipe-organ shaped tubes)

Hard corals (Scleractinian) are the reef builders.  They create a calcium-carbonate skeleton and can be subdivided into large and small polyp corals.  These corals are generally less tolerant of poor water conditions, and small polyp stoney corals have problems with pests moreso than other corals in the hobby.

Hard, large polyp coral (Acanthastrea sp)

Hard, small polyp coral (Acropora sp)

Problems facing the hobby:
Of course, there are people against the saltwater aquarium hobby for various reasons (cruelty to animals, overharvesting, etc.)  I’ll leave those debates out for now.  However, there are plenty of other issues such as the destruction of natural reefs that could prevent imports.  Devestating storms may suddenly increase or decrease water temperature (causing bleaching), physically damage the corals by impact, or they may introduce pathogens the corals are not able to fight.  Overfishing and blasting may kill unintended organisms, it stresses the local environment, and it destroys reef structures.  Pollution may introduce all types of harmful chemicals, heavy metals, etc.  And, then there’s the invasive species, such as Caulerpa algae in California.

Other problems in the hobby is that it can be a challenging (but rewarding) hobby by itself.  Saltwater aquariums are inherently an unstable environment.  As water evaporates, the salinity in the aquarium rises.  The small the aquarium, the less stable it is.  As salinity is rising, inhabitants are creating waste (ammonia, nitrite, and nitrate), and other inhabitants are depleting minerals.  Plus, saltwater plus electricity just means trouble.

Then…add in pests!  Red bugs act like fleas to Acropora, nudibranchs eat Montiporas, and red Planaria smother every surface available.  Add in Acropora-eating flatworms, stinging anemones, coral-eating starfish, predatory “bugs”, and six foot long coral-eating worms…and you have the stuff of science fiction horror movies. 

Coral-eating Starfish

Hm…not really convinced?
Ok, so maybe I scared you with the last section.  Every reefkeeper will have a horror story or two, but so will every rock climber, skiier, hiker, or any other challenging hobby.  The aquarium hobby comes with its challenges, but the rewards are amazing.  You may even find yourself finally truly understanding and enjoying what you learned in high school chemistry.

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Edwards, N; Beck, AM. Using aquariums in managing Alzheimer’s disease: Increasing   nutrition and improving staff morale. 2003. Pet Care Trust Final Report.
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