There are two schools of thought about things riding in on specimens...could be good or OMG we're doomed.
I belong to the former school. I've had all sorts of things turn up, a beautiful nudi I wish I could have kept alive, couple of live clams (tiny), sea squirts, stomatella snails (wonderful and interesting creatures), various sponges, yellow, blue, etc,xenia, aiptasia, and hordes of mini brittle stars, not to mention algaes, macros, vallonia (bubble), and most noxious of all creatures on earth, caulerpa weed.
I am not, however, plagued by these. Nor do I rush to 'get something to eat x-critter', simply because once it does, the poor thing's going to starve. My tanks are under 100 gallons, which definitely limits what you can do in the 'eats-caulerpla' department. Fish that will are few, and grow to 10". Then you've stopped having a problem algae and have started having a problem fish.
There are a number of cures you can get for an invasive, and if it's fixed to a rock, your best cure is probably hydrogen peroxide as it come from the drugstore bottle: dip the area of the rock (on your kitchen counter) into a dish of H202 and count to thirty, then rinse it really thoroughly (even tap water is ok for this) and put it back in your tank. Most of your rock is still fine, and set it over in a corner temporarily until it stops bubbling, because (believe me!) straight oxygen will burn heck out of stuff. And that's what's in those bubbles. Regard it as 'acid' because it acts like acid. This is why you rinse it. The extra oxygen will disperse in the water and not hurt anything, but any fish investigating the bubbles could be harmed.
The other thing you can do, particularly about algae, is knock the phosphates down to next to nothing. Not nothing. But next to, because some phosphate is useful. Ro/di water doesn't have phosphate. Tapwater conditioned or not---does. This is why you don't set up with conditioned tapwater.
Trick to the knocking-phosphates: you have to get something to absorb it. Phosban and other brands are good at this. For a tank over 10 gallons, you need a phosphate reactor, a simple passthrough device that brings water into contact with GFO (granulated ferric oxide: rusty iron) and locks the phosphate onto the iron. GOod. BAD part is, once it's locked on and saturated, you will get no more help until you change out the GFO. Which can be saturated in a week if you have really bad phosphate. My rule is change it every month until your algae starts to look unhealthy. You have reached the end of the problem. Just let that last batch keep working until you're happy with it. The end is usually very defined and catastrophic for the algae.
Peppermint shrimp will eat aiptasia, all except the biggest and fattest, which I swear they 'farm' to get the tastier babies. Pep shrimp may sample a coral polyp or two, but no real harm, unless that's all you've got; and not all pep shrimp have a taste for anemones. Either have the seller demonstrate they WILL eat them or buy very young shrimps, about 3 in number, and you stand a better chance of having them take to that diet. Yes, even shrimp learn. Caution: do not add them to a tank with anemones. They will become a problem.
Sponges are generally good, sea squirts harmless, clams harmless (though doomed: our tanks are too clean).
Crabs are almost 100% not good, and this includes Sally Lightfoots which can get the size of dinner plates, and even mithrax, which may take a piece of slow moving fish fins. Micro-hermits (especially scarlets) are very good, and can walk on your corals without hurting them. Decorator crabs and others that inhabit corals are fine, but if you spot a crab you didn't plan on and can lift him and his hiding rock out to your sump until you can get an id, this would be a good idea.
Hope that helps reassure folk there ARE cures for problems you can acquire along with 'good' hitchhikers.
I belong to the former school. I've had all sorts of things turn up, a beautiful nudi I wish I could have kept alive, couple of live clams (tiny), sea squirts, stomatella snails (wonderful and interesting creatures), various sponges, yellow, blue, etc,xenia, aiptasia, and hordes of mini brittle stars, not to mention algaes, macros, vallonia (bubble), and most noxious of all creatures on earth, caulerpa weed.
I am not, however, plagued by these. Nor do I rush to 'get something to eat x-critter', simply because once it does, the poor thing's going to starve. My tanks are under 100 gallons, which definitely limits what you can do in the 'eats-caulerpla' department. Fish that will are few, and grow to 10". Then you've stopped having a problem algae and have started having a problem fish.
There are a number of cures you can get for an invasive, and if it's fixed to a rock, your best cure is probably hydrogen peroxide as it come from the drugstore bottle: dip the area of the rock (on your kitchen counter) into a dish of H202 and count to thirty, then rinse it really thoroughly (even tap water is ok for this) and put it back in your tank. Most of your rock is still fine, and set it over in a corner temporarily until it stops bubbling, because (believe me!) straight oxygen will burn heck out of stuff. And that's what's in those bubbles. Regard it as 'acid' because it acts like acid. This is why you rinse it. The extra oxygen will disperse in the water and not hurt anything, but any fish investigating the bubbles could be harmed.
The other thing you can do, particularly about algae, is knock the phosphates down to next to nothing. Not nothing. But next to, because some phosphate is useful. Ro/di water doesn't have phosphate. Tapwater conditioned or not---does. This is why you don't set up with conditioned tapwater.
Trick to the knocking-phosphates: you have to get something to absorb it. Phosban and other brands are good at this. For a tank over 10 gallons, you need a phosphate reactor, a simple passthrough device that brings water into contact with GFO (granulated ferric oxide: rusty iron) and locks the phosphate onto the iron. GOod. BAD part is, once it's locked on and saturated, you will get no more help until you change out the GFO. Which can be saturated in a week if you have really bad phosphate. My rule is change it every month until your algae starts to look unhealthy. You have reached the end of the problem. Just let that last batch keep working until you're happy with it. The end is usually very defined and catastrophic for the algae.
Peppermint shrimp will eat aiptasia, all except the biggest and fattest, which I swear they 'farm' to get the tastier babies. Pep shrimp may sample a coral polyp or two, but no real harm, unless that's all you've got; and not all pep shrimp have a taste for anemones. Either have the seller demonstrate they WILL eat them or buy very young shrimps, about 3 in number, and you stand a better chance of having them take to that diet. Yes, even shrimp learn. Caution: do not add them to a tank with anemones. They will become a problem.
Sponges are generally good, sea squirts harmless, clams harmless (though doomed: our tanks are too clean).
Crabs are almost 100% not good, and this includes Sally Lightfoots which can get the size of dinner plates, and even mithrax, which may take a piece of slow moving fish fins. Micro-hermits (especially scarlets) are very good, and can walk on your corals without hurting them. Decorator crabs and others that inhabit corals are fine, but if you spot a crab you didn't plan on and can lift him and his hiding rock out to your sump until you can get an id, this would be a good idea.
Hope that helps reassure folk there ARE cures for problems you can acquire along with 'good' hitchhikers.
