Mr. Saltwater Tank

How to Choose Fish For Your Saltwater Tank

Choosing what fish to put your saltwater tank is as important a decision as choosing which equipment to buy. And all too often, the wrong fish in put in the wrong tank which leads to disastrous results.

Here’s how to pick your finned friends to make sure your tank thrives.

Browse the Store! Questions?

Comments for this article (46)

  • Edward says:

    I wondered if I could get your input on a Purple Tang for my tank. My tank is 75 gallons with a 35 gallon refugium/sump. I have 75lbs of live rock (bought dead rock and seeded it), 10 or so pounds of rubble in my sump. I also have a SWC 160 cone protein skimmer. My current inhabitants are 7 blue green chromis ( I am more then likely going to return 2-3 of them) . My future inhabitants will be 2 tank bred clowns ( thinking of some picasso perculas) and a sand sifting goby of some type. Like you the Purple tang is my favorite fish and any input would be greatly appreciated. Thanks!

  • Chris Gudino says:

    I prefer to get aquacultured fish and corals, Its great you mentioned it.

    Maybe you can do a segment on that next! Go ORA!

  • leebrindley says:

    i dont understand this damsel thing i have a blue and yellow one its so shy and my clowns chace it round everywere lol

  • Mason says:

    love the new HD looks great as always love the show have a semi destructive Christmas wrasse in my tank right now growing like crazy.

  • Murat says:

    As i expected, thank you Mark..!!!Right now i have a fire gobby issue,they were good friends until today, now one is badly beaten and threathened by other one…i heard that they should be kept in odd numbers, not couple or even? is that true ?

  • Just Jen says:

    Mark, THANK YOU so much for doing this. I’m getting ready to graduate from my FW EcoPico to my first SW tank (just trying to convince my Hubs that it’s okay) and I will reference this post when stocking it. Very informative and WELL DONE. Cheers!

  • Andy says:

    Edward –
    No. A purple should really only be in a 125+ tank.

  • jon says:

    i have a shy purple tang that is my 75g
    i saved if from a guy who had it in 30g tank

  • jim says:

    Chunking fish into the tank, eh? No, I wouldn’t recommend that either… 🙂

  • john says:

    Mark thanks once again for a very informative video. I have done alot of the things you have been talking about and you have made my experience in this hobby really enjoyable. I actually have my clownfish literally eating out of my hand. My daughters can’t wait until I feed my fish to see this. My wife was a little taken aback by how much I spent on my 90g tank but now that she sees the end results she asks what can we put into the tank next ,it’s tough having to make her wait 😉

  • nadeem says:

    hi Mr. salt water. i m planning to setup a new marine tank do u have any video which show the complete setup. i wanted to know the about the sand part. how much time it take to mature the tank water?

  • video on setting up a tank yet. Sand…shoot for a 2″ sand bed. For cycling your tank, watch this episode.

  • John…you are welcome!

  • Murat…the odd number rule is a good one for firefish, and I prefer to just keep 1. I’ve never had luck with keeping a lot of them.

  • Jen…send me your phone number and let me have a man-to-man talk with the hubby!

  • Jon…thanks for saving the purple tang! Since he is acting shy, keep an eye on him as he might be stressed in your tank. If he refuses to eat and/or has frequent ick outbreaks, consider moving him to a bigger home. *cough* reason to upgrade…

  • Edward..I’d for sure trade in some of the chromis. The long run you’ll end up with just one as one tends to be dominant and the others always disappear.

    Make sure your rock work is aquascaped so your tang has lots of open swimming room as well good places to hide. This will help him feel more comfortable.

  • Matt says:

    I’m just a few weeks/months from getting my first marine tank… I’ve kept fw for years… I’ve just done a two day marathon of watching all your vids and cross referencing your advice (and enjoying the laughs).. the advice you give is without doubt the most straight forward and sensible I’ve found to date! Mark your a top man…

    Any suggestions for my first few fish after CUC (also a great vid cheers 😉 )… They HAVE to be tank bred or responsibly sourced or I won’t entertain having them! Corals are a whole different bunch of questions!


  • Not so sure I’m 100% on board with the “no damselfish” rule….afterall Mark, you have one swimming around behind you (Chromis are Damselfish afterall 😉 ). Not all damsels are evil. Know thy fish, do homework before you buy – research a fish before you buy it…not walking into the store and picking on the spot!

  • Matt P…you are correct about Chromis being damsels…but the chromis have a much better temperament in my experience. Agreed that not all damsels are evil and I’m not willing to take the risk. Plus I see too many people buying them as great “starter fish” and paying for it later so its easier to avoid them. Now if you can use your fish breeding ninja skills to make a docile damsel that does what it is told, let me know and i’ll promote it for you!

  • Matt…thanks for choosing tank bred fish. Captive bred clowns are always a good choice for starter fish. Just make sure you use the Dr. Tim’s bacteria ( to cycle your tank.

  • Matt says:

    Mark… Cheers for the advice… Its funny you should mention Dr. Tim’s bacteria… I’m in the UK and entered a competition run by Marine Habitat Magazine and won a big bottle of the stuff… Not 10 mins before I found out I won I’d watched your ‘Snake Oil’ vid… Imagine how chuffed to bits I was!

    So… when are you setting up a forum? Its about time you did!

  • Chrysiptera paresema and C. hemicyanea are two “mellow” and common damsels for most people – only time these guys would probably cause any real problems is when mating. I keep Chrysiptera starkii, which really only chases the other C. starkii and has only ever killed another C. starkii (C. starkii is probably a one per tank for most smaller tanks). I suspect, but do not know firsthand, that C. galba is probably very mellow as well.

  • Kevin says:

    I don’t know how it is for the US, but where i live (the Netherlands) i can look at one of the largest importers website and download the stocklist, it shows some information about the fish, and corals. And also shows if the fish come from somebody who was breeding them.

    One thing I noticed, you say everywhere, no damsels, however I think you got one in your tank too, and it’s as far as I think the only one that can be kept in the tank.

    Anyhow perfect story, really nice, I see some differences in the tang world especially the ones you say keep them in the store, over here, most would say, ok, you can keep them, but run UV, and have at least 200 gallons of water.

    It’s always hard to find a good shortlist on how to find and choose your fish. This is a good start for anybody capable of understanding English!

  • MILIND KAWLI says:

    thanks for the great advice…. i am setting up my tank now & i am sure that i will follow your advice while choosing new fish…. NO DAMSEL 🙂

  • David says:

    HI Mark, great video. Not sure i agree with you on the powder blue and Achilles tangs though? Could you expand your reasoning behind not having them in an aquarium..ever? Is this purely the ich problem often seen with these species?

  • Anthony says:

    Hey mark great vid. quick question. I picked up two ocellaris clowns a couple months back. the guy at my lfs said they were young enough to become a mated pair. They are almost 2 inches long now and still fighting. Im hoping they will still pair up, but im not sure. Any ideas?


  • If they are both the same size they won’t pair up. You need one that is a lot larger then the other so that one clown stays female and the smaller one switches to be male. Age really has nothing to do with it.

  • Richard Belcher says:

    Great video & great advice as always. Loved the way your Mandarin was swimming around in shot while you delivered your sage opinion on keeping them 🙂 Keep the vids coming – Loving the updates from the other side of the “pond”

    PS: Are the a MTB or a roadie (maybe a bit a both?) A vid on the bikes would be good, just ensure not to mix the “saltwater” with the chains – Yikes!

  • Richard Belcher says:

    Hummmm, either I can’t type or… ok, so I can’t ytpe 🙂 I meant – Are YOU a mountain biker or a roadie?

  • Warren says:

    Great video Mark!

  • Richard…roadie!

  • Phastroh says:

    I have a Coral Beauty Angel and a Flame Angel and they are getting along fine and do not eat my coral.

    Any thoughts?

  • Dale says:

    Mark, where do Rabbitfish fall on your job scale (algae eater, cleanup crew, etc? Would you recommend a foxface as a reefsafe fish? Thanks.

  • Christina says:


    We have put a Christmas wrasse into our 20 gallon tank three days ago and have never seen him. We have two clown fish and one banggai cardinalfish and several coral. Should I be concerned?

    Thank you!

  • Christina..first, 20 gallons is too small for that wrasse. He’d be happier in a 55g+ tank as he needs lots of room to swim around to feel comfortable.

    Also, wrasses sometimes hide out for days only to reappear out of nowhere. He might have kicked the bucket and unless you have a strong clean up crew (CUC) you could have found him

  • clock511 says:

    this hobby is so cool! 🙂

  • chris says:

    THANK YOU i hate it when people buy fish taken from the wild

  • Brian Davis says:

    Awesome information! Thank you so much for the details! I referred to my Damsels as the Blue Devil Bastard fish from Hell. I learned early on through my mistake purchasing them, I made a trap, caught them, and took them back after observing their behavior…never again will I own these buttheads, lol. Great video man! Take care.


  • Patrick says:

    Hey Mark, I am brand new to the sw hobby and got a 34g solana that I am going to be starting up. What type of fish is best suited for this tank?


  • davidcrush says:

    Hi I was wondering what I can stock a 46 bow with I like tangs and clowns

  • Thomas Davis says:

    When I click on the video it keeps bringing me to Vimeo. Is there any other way to view this video?

  • Tom De Meulder says:

    I really need your advice here.
    I have purchased a niger triggerfish and now i don’t know for sure if this was a good idea, I have a 93g tank and he is about 3 inches big.
    The store keeper said it was the calmest trigger fish but after some reading i panicked.
    I’m a little worried if he will eat my snails and shrimps? can you give me some advise please. perhaps its better to take him out or is there a way to keep him in my tank because it’s such a beautiful fish.

  • Sean says:

    Damsel fish are a pain in the arse… New to the hobby myself.. Set up a 55galln tank pair of clowns yellow tank gold rim tang and afew damsel fish that fight each other and kill things.. The little b@@t@@@s. hahah thanks for the videos mark… Always look for help via mr saltwater tank tv

Comments are closed.