Choosing marine life for your saltwater aquarium is really fun.
However, it’s easy to make mistakes you will regret by choosing something that is too hard to care for, sick, carries disease or is not compatible with the rest of your marine aquarium inhabitants.
A really good idea in deciding what marine fish and invertebrates you really want is to make a saltwater aquarium plan before setting up your tank if you haven’t already.
Here you would list all the marine life you are interested in then research them in terms of:
⪼ Care required (and how easy they are to care for)
⪼ Size (at purchase and at maturity)
⪼ Diet (food and feeding)
⪼ Behavior (shy fish cant be put with boisterous ones too easily)
⪼ Set-up/water conditions required (additives, water movement, light levels)
⪼ Compatibility with other marine life (will they get along?)
⪼ Degree of aggression/territoriality (if high will cause other species stress)
⪼ Can they be kept in pairs or groups?
Now you would group them all together based on such things as set-up required (fish only, FOWLR, reef aquarium), compatibility, and type of community.
The idea is to see what fits into your plan and come up with a harmonious but interesting and vibrant community that will get along and have similar or manageable requirements.
Obviously each species can go into more than one group. Now you choose which group would be best and coolest for you. And this is what you will go with.
It is important to note that all marine life is aggressive to a degree because they must be competitive in nature, so you are looking out for overly aggressive and bullying species.
Doing this planning before you set up your aquarium gives you a holistic approach allowing you to set up and use equipment centered on exactly what you want to keep.
If you are just starting out you would choose one or two of the species in your group that are most hardy and start by adding them first.
Now you have chosen what species you want you now need to choose your specimen. Where possible ALWAYS choose captive bred species, these species are sustainable, will be in better health, are much more hardy, more tolerant to adverse water conditions and are much more likely to eat whatever you give them.
Most importantly if you purchase captive bred species you can be 100% sure that you are not inadvertently funding illegal, reef destroying and cruel capture methods somewhere in the world.
If you can’t purchase the particular species you want as captive bred, then you will need to find a reputable fish stockist. They must be professional, have a good reputation and most importantly have all their marine life collected from sustainable sources. Ask them where they got their fish and if its not legitimate do not buy from them.
Now you need to select a healthy specimen.
Start by looking at the size; it needs to be not too small or scrawny and not too big as these sizes are less likely to adapt to your aquarium conditions and more likely to be in worse shape after capture and shipping. Large specimens are also less likely to adapt to the change of diet and be more ensconced in their behavior.
A key indicator to a fish’s health is how well it is eating. You will definitely want to observe this at the fish store by asking the staff to feed or come back at feeding time. The fish should eat actively and should be alert and competitive with the other fish in getting food. It should eat heartily and have a good appetite.
Another key indicator of health is to observe the fish itself; watch how it swims, breathes and behaves looking for anything abnormal. A healthy fish is active, alert and looks healthy with vibrant colors.
Study its eyes; both should be bright and clear and not sunken or bulging out.
Study the body for evidence of physical damage and external parasites, Ich and velvet will show up as white spots or dust especially at eyes, mouth and where the fins join the body. The fish will also be breathing rapidly too.
Shallow breathing, inactivity, looking dazed and confused and sunken or too small looking eyes are a good indicator of cyanide capture; avoid this fish as it may die!
A healthy fish will be interactively swimming around its tank mates and be curious about its surroundings and you.
Now that you have selected your healthy fish you need to ask how long it has been at the store.
Never buy a brand new fish; give it a few days to adjust and de-stress. Th gives you time to see whether it survives and/or has a disease. What you can do is ask the store to put it on hold, put down a deposit if you must and wait around a week or so to ensure that it remains in good condition.
When you get your new purchase home remember to quarantine it and acclimatize it correctly to maximize its chance of success in your aquarium and to avoid spreading any potential diseases to your existing marine life.
Selecting healthy marine invertebrates is much more difficult but generally if it looks appealing and healthy is usually is.
Here are some general rules of thumb for specific invertebrates:
Sea Urchins should not be shedding spines one or two broken off around the aquarium is fine but anymore than this is a bad sign.
Sea fans and sea whips should be damage free and preferably attached to a bit of live rock. Polyps that are fully extended are a sign of good health.
Sea Anemones unbelievably can be dyed for visual impact, avoid these unusually colored specimens. Their basal discs, columns and all tentacles should be intact and healthy looking. Beware of constantly retracted individuals. Collapsed anemones will most likely have bubbles of air trapped inside them from improper handling.
Molluscs will have no shell damage and a fully extended mantle and be exploring the tank.
Corals should be undamaged (not too many bits broken off) and of uniform coloration and not bleached looking. There should be no obvious area of tissue absence or overly black or white regions. Avoid specimens with hair algal growth.
Sponges should always be submersed in water or else they can easily die, make sure your supplier knows this before buying from them.
Sea stars should not be showing lesions or have a patched appearance, they should be looking healthy and normal.
If you take your time to look for happy, healthy marine pets and can recognize the tell-tale signs of stress and disease then you should be able to avoid the cost and emotion of sick and dying marine life in your saltwater aquarium.