Multiple factors increase your odds for and against.
1. a 'clean' fish store. No store can be immaculate, and if you take a close look, most stores operate multiple tanks off the same sump, which means 'goes around comes around.' If you spot sick fish in one tank, look where the hoses come from and what other tanks are connected. There are times to walk out and wait for the store to get itself in order.
2. a knowledgeable buyer. Pity-buys (oh, the poor shy one...) are lethal. If a fish is rescue-able it's not likely going to be a novice that saves it. Don't get the shy one, the timid one, the one the others are picking on. Get the fattest, fin-perfect terror in the lot. Which will ALSO rescue the poor shy one from him.
3. Knowledge of the enemy. It is NOT true that stress causes ich. Ich is an animal that attacks your fish to get nutrients to breed. It lives in the sandbed. In the case of fish like wrasses which sleep in particular spots in the sandbed, it's a guarantee of a victim. Slime coat can protect your fish, and there are products that encourage the slime coat. Think of it as an outer skin, which, if it gets thinned or wounded, exposes the fish's flesh to whatever comes. This is why I am not a fan of freshwater dips and meds that may be hard on the slime coat. If you want to help your fish fight off parasites, get the Salifert DKH Alkalinity test, do it weekly, and keep that reading around 8.3 forever. You can also feed Selcon (vitamins and nutrients) to assist a fish you're worried about. Most of all, if you have one case of ich---EVERYBODY THAT'S A FISH should go immediately into treatment, and the safest one is TTM (tank transfer method). Corals and inverts are immune to ich, so use the 72 days your tank has to endure with NO fish in it (to starve out the ich) to nurture your corals and snails.
4. Starting with healthy fish. Yep. That's why you buy the mean guy with perfect finnage and tightly closed gills. Watch those gills. If a fish is swimming around with distended gills, that could be ich, without the dots that advertise its presence under the skin.
5. Avoiding cleaner shrimp and such---that may actually breach the slime coat and make raw areas if the tank is too small. They can really pester a fish to its detriment. And they can't do a thing about ich. It's deep under the skin. It's not the pimple. It's what's in it.
6. Avoiding overstocking. This increases aggression---MOST ALL marine fish are aggressive if crowded or faced with an unwanted mate. Singles are generally best (clowns do ok as pairs) and fish sniping at each other can create damaged slime coats and generally run down the health and resistance of the picked-on fish. You can get that cute little rabbitfish that's so small---and find he grows rapidly to 5-10 inches in size and is freaking about too little space: that's the point when your other fish start dying mysteriously with a red spot somewhere on their bodies---rabbitfish venom. It's that topfin. And rabbits aren't the only fish that can go bozo when they outgrow their tank. Stock for the ADULT size and you will both keep healthy fish and have them grow into their potential. Remember, every time you bring a new fish---you are risking ich and other problems. So keep your stocking sensible and planned, and eliminate the angst and cost of a rotating door for new specimens. If you're in this hobby, you're likely to have many tanks or setups over time---I started at age seven or so and have rarely been without a tank. Expect that. And put off your desire for some species until you're setting up again.
1. a 'clean' fish store. No store can be immaculate, and if you take a close look, most stores operate multiple tanks off the same sump, which means 'goes around comes around.' If you spot sick fish in one tank, look where the hoses come from and what other tanks are connected. There are times to walk out and wait for the store to get itself in order.
2. a knowledgeable buyer. Pity-buys (oh, the poor shy one...) are lethal. If a fish is rescue-able it's not likely going to be a novice that saves it. Don't get the shy one, the timid one, the one the others are picking on. Get the fattest, fin-perfect terror in the lot. Which will ALSO rescue the poor shy one from him.
3. Knowledge of the enemy. It is NOT true that stress causes ich. Ich is an animal that attacks your fish to get nutrients to breed. It lives in the sandbed. In the case of fish like wrasses which sleep in particular spots in the sandbed, it's a guarantee of a victim. Slime coat can protect your fish, and there are products that encourage the slime coat. Think of it as an outer skin, which, if it gets thinned or wounded, exposes the fish's flesh to whatever comes. This is why I am not a fan of freshwater dips and meds that may be hard on the slime coat. If you want to help your fish fight off parasites, get the Salifert DKH Alkalinity test, do it weekly, and keep that reading around 8.3 forever. You can also feed Selcon (vitamins and nutrients) to assist a fish you're worried about. Most of all, if you have one case of ich---EVERYBODY THAT'S A FISH should go immediately into treatment, and the safest one is TTM (tank transfer method). Corals and inverts are immune to ich, so use the 72 days your tank has to endure with NO fish in it (to starve out the ich) to nurture your corals and snails.
4. Starting with healthy fish. Yep. That's why you buy the mean guy with perfect finnage and tightly closed gills. Watch those gills. If a fish is swimming around with distended gills, that could be ich, without the dots that advertise its presence under the skin.
5. Avoiding cleaner shrimp and such---that may actually breach the slime coat and make raw areas if the tank is too small. They can really pester a fish to its detriment. And they can't do a thing about ich. It's deep under the skin. It's not the pimple. It's what's in it.
6. Avoiding overstocking. This increases aggression---MOST ALL marine fish are aggressive if crowded or faced with an unwanted mate. Singles are generally best (clowns do ok as pairs) and fish sniping at each other can create damaged slime coats and generally run down the health and resistance of the picked-on fish. You can get that cute little rabbitfish that's so small---and find he grows rapidly to 5-10 inches in size and is freaking about too little space: that's the point when your other fish start dying mysteriously with a red spot somewhere on their bodies---rabbitfish venom. It's that topfin. And rabbits aren't the only fish that can go bozo when they outgrow their tank. Stock for the ADULT size and you will both keep healthy fish and have them grow into their potential. Remember, every time you bring a new fish---you are risking ich and other problems. So keep your stocking sensible and planned, and eliminate the angst and cost of a rotating door for new specimens. If you're in this hobby, you're likely to have many tanks or setups over time---I started at age seven or so and have rarely been without a tank. Expect that. And put off your desire for some species until you're setting up again.
