Biosecurity and Quarantine

Pathogens live in the water, and you can't see them. Each system is its own island: its own water, its own animals, its own pathogens. If one system gets sick, the others stay safe as long as nothing carries water between them. Biosecurity is the habits that keep those islands apart, and that stop new animals bringing new problems in.

Clean-looking isn't clean. A net used in four systems without sterilizing links all four: if one gets sick, all four have to be watched. Every rule in this module has a reason, and knowing the reason is what gets it right when something new happens (Module 1). Personal safety around tank water is in Module 2.

Nets, buckets, cups, hoses, pumps and siphons hold water inside and drops outside. pH and salinity pens are dipped into one system, then the next. Wet hands and wet gloves go from tank to tank. Bubbles bursting and water splashing throw tiny drops into nearby tanks. Shipping bag water, and every animal, bring their own pathogens.

Never mix water between animals or between systems, and never move equipment between them without sterilizing it first. A UV sterilizer doesn't stop a disease spreading between animals that share the same water: once a problem is in a system, every animal in it shares it (Module 21).

Do everything for one system, log it, then move to the next. Bouncing between systems is how tools, water and hands carry problems around. Care for the most vulnerable animals first and quarantine or sick systems last, so nothing comes back from quarantine into a healthy system.

Wash hands and spray them with alcohol before switching systems, even between individual pair boxes on one rack: rub the hands together so every part, including under the nails, gets spray, then let them dry. Each system's own tools stay with it. A shared tool is sterilized before it goes into the next system.

Slime, algae and detritus shield pathogens from a disinfectant and use it up, so scrub and rinse first. Disinfectants need contact time: a quick dip does almost nothing. Rinse afterward, because disinfectant left on a tool goes into the next system, and never pour used disinfectant into a system or a sump.

Anything that's been in the sink is washed and sterilized before it's used again, and put away after use. Buckets are washed with hot water, sprayed with alcohol and left to dry. Pumps and hoses that move salt water in or out are washed and sterilized before they go to another system. No buckets of water are left sitting around, and no equipment is left out.

A dishwasher's heated cycle is the first choice for anything non-electronic: nets, cups, buckets, tubing, sponges, filter socks. Fill it, run it, done. The only thing added is oxygen bleach (sodium percarbonate). Tools that can't go in a dishwasher, such as pH and salinity pens, go through the iodine cup. Alcohol spray is for hands and for surfaces after washing.

The iodine cup: measure 5 ml of povidone-iodine with a graduated cup into 250 ml of fresh water. Rinse the tool in fresh water first, then soak it for at least 10 minutes with every part that touched tank water under the surface. Rinse it in RO water before it goes into another system. Iodine is brown, and the color fades as it's used up; mix a fresh cup every day, or sooner if it fades. A pH pen goes back into its storage cap after the rinse, never left in the cup.

Shipping bag water never goes into a system, and quarantine water never goes into a display. Move the animal, not the water (Module 25 covers acclimation). No animal is moved between systems or introduced into a system without two rinses: after acclimation in its own container, it goes through water from the system it's going into, put into two separate buckets, one after the other, so as little of its old water as possible goes with it. Acclimation cups, drip lines and containers are equipment: sterilize them between animals and between shipments. Water taken out of a system for any reason never goes back into another one.

Some animals need stricter rules. Once a carpet anemone such as S. gigantea is healthy and established in a system, a new anemone never goes into that system's water, including the sump; a new carpet finishes quarantine first. Dead animals come out right away: a dead animal rots, adds waste and can spread what killed it.

Quarantine holds a new arrival in a separate system, with its own water and its own equipment, so any problem it carries stays there. The quarantine system needs stable, mature water: arrivals do worst in small containers and holding bins without established filtration. Mesh containers are never used (Module 25). Quarantine is worked last, after every healthy system.

Quarantine only works if it's kept separate. Shared nets, shared pens without the iodine cup, splashes from a quarantine tank into its neighbor, or quarantine water moved with the animal all undo it. A hospital tank is different: it's for treating animals that are already sick (Module 30).

Published quarantine periods for marine fish run from at least 10 days to 6 weeks or more. Watch every fish every day: how it breathes, swims, eats, and how its fins and skin look. Gill flaring, rapid breathing or any fin damage are signs to act on right away, not to wait out (Module 30 covers treatment). A fish that won't eat is a health warning.

Write down what you see each day. A log turns "it looked a bit off" into a record of when it started and what changed, which is what a treatment decision needs (Module 7).

New corals and invertebrates can carry parasites and predators, such as coral-eating nudibranchs, into a display. Dip each new coral outside the tank, never in a display, in a fresh mix for each frag, then rinse it in clean tank water. Remove the frag plug where possible, because pest eggs are often found where the frag is glued on. Inspect each one with a light every morning and again after the lights go out, when some pests come out.

Plan on 4 to 8 weeks of coral quarantine. Pest eggs can hide in crevices and hatch later, so re-dip whenever pests turn up and add another 4 weeks after each re-dip. Live rock is the exception: it's used for the life it brings, accepting what comes with it (Module 22).

Copper is used to treat some fish diseases (Module 30), and it's toxic to invertebrates. Any tank, rock, sand or equipment that has ever held copper is fish-only for good. Label it, keep it apart, and never let it near an invertebrate system.

Any equipment that belongs to a quarantine or treatment system stays with that system. If it has to move, it's sterilized first, and anything that held copper doesn't move to an invertebrate system at all.

The same problem in two systems that share no water: something carried it, so trace what moved between them: a net, a bucket, a pen, gloves, a person, an animal, splashes. A pale iodine cup: tools that went through it may not be sterilized; mix fresh and put them through again. A bucket of water left sitting: find where it came from and where it was going, and empty and sterilize it. Disease after a new arrival: check whether bag water went in or quarantine was skipped.

Fix the habit, not just the day. Then watch every system the carrier touched (Module 1).