Tank Mates for Seahorses-Saltwater Fish


Tank Mates for Seahorses- Saltwater Fish

This article discuses many seahorse safe fish and fish to avoid with seahorses! We also cover some of the species that can be kept "with caution" and some tips on how to possibly be more successful with these species. 

Most people like a variety and there are a lot of different saltwater fish that can be kept with your seahorses. Adding fish to your seahorse aquarium can add lots of personality and some may even help as "clean-up crew". 

This guide is for larger species of seahorses including H. erectusH. comesH. Reidi, and more. This list is NOT for Dwarf seahorse, H. zosterae or coldwater seahorse species such as H. abdominalis


Peaceful Fish Species Safe to Keep with your Seahorses

This is a list of fish we have come up with from our experience and speaking with many seahorse keepers. We are always adding new species to this list to help give other keepers ideas of new species that are friendly to keep with their seahorses. There are many other species out there that would probably be ok with seahorses but this list can help give you some general ideas of fish considered seahorse safe.

It is important to remember that just like people, all fish are individuals. Some individuals can display behavior out of the norm for their species and not work out. It is also important to research individual fish to see if they will cohabit peacefully with other fish species you may wish to keep with them. If you have any specific questions we are happy to help.

Captive Bred Fish

Now days more and more saltwater fish are being captive bred and aquacultured. Captive bred fish are those born and raised in a closed system aquarium. Many fish farms captive breeding marine fish practice strict quarantine protocols and bio-security at their farms. This means they take precautions to prevent pathogens with their fish. Wild caught fish can often carry a variety of pathogens and may be possibly exposed to pathogens along the supply chain. 

Captive bred fish being born and raised in an aquarium are generally more bold, active, more readily feeding to prepared foods, and use to life in an aquarium. These captive bred fish tend to acclimate and settle into their new homes easily and quickly. 

Collected Fish 

There are also many sustainably collected saltwater fish that can make great seahorse tank-mates. Some species are not available captive bred and in some cases collected fish can actually be more sustainable than aquacultured fish. Some species are all around hardy and transition well to aquariums. Supporting sustainable fisheries can help support local communities and help conserve as well as add economical value to local reefs. Giving these local resources value gives the people of the communities more incentive to protect their local environment.

It is important to make sure you practice good quarantine with any new arrivals, but especially collected specimens to ensure you do not bring in any unwanted pathogens. 


There is a huge diversity of saltwater gobies. This is one of our favorite groups of fish as there is so much variety, they are hardy, lots of personality, many types can be kept together, they are peaceful and of course go nicely with seahorses. Some are known to have a symbiotic relationship with pistol shrimp which can be super neat to observe in your home aquarium. 

Most of these popular fish do best in an aquarium with sand (not bare-bottom). There are a lot of interesting behaviors that can be observed with different species. They do not tend to be shy! Many goby species are available captive bred as well.These fish tend to be easy to keep and hardy.

  • Court Jester Goby, Koumansetta rainfordi
  • Hector's Goby, Koumansetta hectori
  • Diamond Watchman Goby, Valenciennea puellaris
  • Sleeper Gold Head Goby, Valenciennea strigata
  • Sleeper Blue Dot Goby, Valenciennea sexguttata
  • Sleeper Striped Goby, Valenciennea longipinnis
  • Hi Fin Red Banded Goby, Stonogobiops nematodes
  • Yellow Prawn Goby, Cryptocentrus cinctus
  • Bluespotted Watchman Goby, Cryptocentrus pavoninoides
  • Yellow Clown Goby, Gobiodon okinawae
  • Black Clown Goby, Gobiodon strangulatus
  • Two Spot Goby, Signigobius biocellatus
  • Pink Spotted Watchman Goby, Cryptocentrus leptocephalus
  • Yasha White Ray Shrimp Goby, Stonogobiops yasha
  • Orange Spotted Goby, Amblyeleotris guttata
  • Steinitz Goby, Amblyeleotris steinitzi
  • Pinkbar Goby, Amblyeleotris aurora
  • Orangemarked Goby, Amblygobius decussatus
  • Wide-barred Shrimp Goby, Amblyeleotris latifasciata
  • Wheeler's Shrimp Goby, Amblyeleotris wheeleri
  • Orange Stripe Prawn Goby, Amblyeleotris randalli
  • Catalina Goby, Lythrypnus dalli (colder water species ~62-72 F)
  • Neon Blue Goby, Elactinus oceanops
  • Red Neon Eviota Goby, Eviota nigriventris
  • Gold Neon Eviota Goby, Eviota pellucida
  • Sharknose Goby, Eviota evelynae
  • Tangaroa Goby, Ctenogobiops tangaroai
  • Masked Goby, Coryphopterus personatus
  • Crested Oyster Goby, Cryptocentroides gobiodes
  • Black Barred Convict Goby, Priolepis nocturna
  • Yellow Priolepis Goby, Priolepis aureoviridis
  • Dracula Goby, Stonogobiops dracula
  • Jaguar Goby, Gobiopsis quinquecincta


Dartfish are another hardy, peaceful, colorful fish safe to keep with seahorses. These are not available captive bred but collected dartfish are hardy fish. They do best in an aquarium with lots of hiding spaces. Once settled into their aquarium, they tend to be pretty active and out and about. 

Dartfish are jumpy and having a cover over your aquarium is pretty much a must with these guys! Having a sandbed is recommend. 

These dartfish do best as singles or bonded pairs in the same aquarium:

  • Red Firefish, Nemateleotris magnifica 
  • Purple Firefish, Nemateleotris decora 
  • Exquisite Firefish, Nemateleotris exquisita 
  • Helfrichi Firefish, Nemateleotris helfrichi 

These dartfish do well in groups:

  • Scissortail Dartfish, Ptereleotris evides 
  • Zebra Barred Dartfish, Ptereleotris zebra 
  • Blue Gudgeon Dartfish, Ptereleotris heteroptera 
  • Lined Dartfish, Ptereleotris grammica


These fish are full of personality! They absolutely need a sand-bed as they create burrows close to the rock-work. They are colorful and really neat little fish to watch! These are jumpy fish. Having a cover over your aquarium is a must to keep them from jumpy out of the aquarium. Captive bred specimens are not available but collected specimens tend to settle into their aquarium quite well when properly cared for and the right environment is provided for them.

  • Yellowhead Jawfish, Opistognathus aurifrons
  • Blue Dot Jawfish, Opistognathus rosenblatti


Dragonets are one of the most eye-catching marine fish out there! They do however need a proper setup to thrive long term!

These little fish have high metabolisms and need to graze on live-rock (copepods and other micro-fauna) throughout the day. Having an establish, large aquarium such as 60+ plus gallons, with lots of liverock is highly recommended for long term success. Also having a refugium can help make sure the aquarium has a healthy population of copepods for your dragonette. These should be kept single species or a bonded pair in a tank. They do not do well in groups. 

  • Mandarin, Synchiropus splendidus
  • Red Mandarin, Synchiropus splendidus
  • Spotted Mandarin, Synchiropus picturatus
  • Scooter Dragonet, Synchiropus ocellatus
  • Red Scooter Dragonet, Synchiropus stellatus


Another colorful small peaceful group of fish. They like lots of hiding places. If you are adding multiples of the same species it is best to do this at the same time. Once an individual is established the aquarium they can become territorial and adding another later on can be challenging. 

These are really hardy fish!

  • Royal Gramma, Gramma loreto
  • Black Cap Basslet, Gramma melacara
  • Chalk Bass, Serranus tortugarum
  • Yellow Assessor, Assessor flavissimus 
  • Randall's Assessor, Assessor randalli

Cardinal Fish

Another small peaceful fish. Many are available captive bred. Cardinal fish are mouth brooders and may even breed in your aquarium. They can be kept singly, as a pair or in a group. We really like to keep them in a group as it is neat to see them school!

Note: They can be fast at eating food. If you are concerned about them competing with your seahorses for food we recommend training your seahorses to feed from a feeding station so they get plenty to eat. This is not always a must but a helpful tip. Pajama and Banggai cardinal fish are our favorites!

  • Kaudern's Cardinalfish or Banggai Cardinal, Pterapogon kauderni
  • Pajama Cardinalfish, Sphaeramia nematoptera
  • Longspine Cardinalfish, Zoramia leptacantha
  • Yellowstriped Cardinalfish, Ostorhinchus cyanosoma
  • Flame Cardinalfish, Apogon spp.
  • Yellow Cardinalfish, Ostorhinchus luteus
  • Black Cardinalfish, Apogonichthyoides melas

Dwarf Filefish

Many of the Dwarf filefish max out at about 3 inches in size. Captive bred specimens are becoming more commonly available. These specimens are hardy, peaceful fish. We recommend keeping them singly or adding two of the same species at the same time. They are really unique looking fish. 

  • Aiptasia Eating Filefish or Bristletail Filefish, Acreichthys tomentosus
  • Radial Filefish, Acreichthys radiatus
  • Whitespotted Pygmy Filefish, R. ercodes

Clownfish (Amphiprion ocellaris and Amphiprion percula)

If you decide to try keeping clownfish with your seahorses we recommend sticking with either A. ocellaris or A. percula. These two species of clownfish are among the more peaceful species and what we recommend if you are going to try keeping them with your seahorses. Clownfish are an iconic marine aquarium fish species and very popular. Clownfish are commonly available captive bred these days and are very hardy fish. There are also lots of really neat and fun selective bred "Designer Clownfish" available.

Mature breeding pairs of clownfish can sometimes become territorial so you do want to keep an eye on them when they mature although they maybe perfectly fine with your seahorses long term with no issues. This is true for not only keeping them with seahorses but other fish in general too. If you are concerned about this, you can also consider keeping a single clownfish rather than a pair. Clownfish are known for their symbiotic relationship with anemones. Clownfish do not need an anemone to thrive and anemones are not seahorse safe. We highly recommend not adding an anemone to your seahorse aquarium! 


These particular blennies are great for algae control and do well with seahorses. Molly Miller blennies are known for also eating the pest, Aiptasia sp. They are best kept in an aquarium with lots of live rock and hiding places so they can setup their own territory and graze on the live rock for algae. They will also eat prepared foods such as pellets, frozen Mysis shrimp ect. It is best to stick with singles of these species in an aquarium unless the aquarium is large with many hiding spots and they are added at the same time. 

  • Sailfin/Algae Blenny, Salarias fasciatus
  • Molly Miller Blenny, Scartella cristata

NOTE: We do not recommend keeping any of the fang blennies with seahorses. We have had reports of fang blennies biting seahorses and since some are slightly venomous their bites can be fatal to seahorses. Seahorses unlike many fish, have a way of getting in the way of another fish's territory and not recognizing the other fish's behavior or territorial warnings. For this reason they are pretty risky to keep with them and we do not recommend it.


Pipefish are cousins of seahorses and closely related. These species are not commonly available captive bred but collected species are commonly available in the trade. If good specimens are available they can be quite hardy when kept properly. Being closely related, good quarantine practice really is important with these as they can carry pathogen seahorses especially are susceptible to. 

  • Dragonface pipefish- Corythoichthys sp.
  • Banded Pipefish-Doryrhamphus dactylophorus
  • Blue Stripe Pipefish-Doryrhamphus excisus
  • Janss' Pipefish-Doryrhamphus janssi
  • Yellow Multibanded Pipefish-D. pessuliferus



General List of Fish to Avoid with seahorses!

These fish are groups we highly do not recommend keeping with seahorses!!! Many of these species grow to be large, are quick eaters, can be aggressive, and do not cohabit well with seahorses. 

Seahorses are slow swimming fish. They do not handle aggression well and can be easily stressed by aggressive fish. Many of these listed fish are fast eaters. Seahorses require a lot of food to thrive longer term. If seahorses are kept with fish that quickly consume the food added to the aquarium they will not get enough to eat long term. 

These fish are species to AVOID:

  • Triggerfish
  • Maroon Clownfish, Premnas biaculeatus
  • Tangs
  • Large Angelfish
  • Pufferfish
  • Lionfish
  • Scorpion fish
  • Groupers
  • Aggressive clownfish, especially mature pairs
  • Damsels
  • Eels
  • Dottybacks
  • Fang Blennies (risk of them biting your seahorses)
  • Rabbitfish
  • Hawkfish
  • Angelers
  • Squirrelfish
  • Large typically non reef-safe wrasse such as Harlequin tusk fish, Coris sp., Halichoeres sp. (Green Coris Wrasse, H. chloropterus, are ok), Thalassoma sp., Novaculichthys sp., and Gomphosus sp. 

Fish to be Cautious with and Possibly Avoid with Seahorses

If you are a new hobbyist it is best to avoid experimenting with these species. With any of these species it may be best to have a larger seahorse aquarium such as 50+ gallons to help give everyone their own space and reduce stress. 

  • Boxfish (Lactoria cornuta, Ostracion cubicus)-While these species tend to be peaceful they can possibly release poison when they are stressed or die in the aquarium. This really doesn't seem to be as common of an occurrence as once thought but could cause issues. The biggest concern we consider is cowfish graze on everything and have strong jaws so there is a chance they can also graze and injure a seahorse.
  • Anthias- Most species require a lot of food and multiple daily feedings to thrive. We recommend having an established aquarium for them with lots of liverock. Again, we recommend starting with small young individuals if you plan to try these with your seahorses. In addition, we recommend sticking to small species that do not exceed ~3 inches with maturity. Seahorses are easily out-competed for food and these fish are quick eaters! Having a "feeding station" for your seahorses will help make sure your seahorses are getting plenty to eat.
  • Fairy wrasses-most smaller species (under ~2-2.5 inches) are ok but some of the larger species could possibly out-compete the seahorses for food. These fish in general can be delicate and it would be best to add them to a well established aquarium with sand and lots of hiding spaces. They have a quick metablism and do best when fed multiple times daily. 

Quarantine Your Fish-Why This is Such an Important Step

It is highly recommended and good practice to quarantine new arrivals, especially wild caught specimens. A quarantine tank can be a simple 10-20 gallon aquarium with a HOB filter and liverock depending on the species. 

There are many ways to quarantine new fish. You can simply observe them for a period of time (ideally a couple weeks or longer) to make sure they are healthy and settled in after shipping. This period of time can allow them to easily get enough to eat, reduce stress, and allow them to condition before being added to the display aquarium. 

In most cases, if a fish is sick it will typically show signs shortly after arrival. If a fish becomes sick it is much easier to treat in a quarantine tank. Starting new arrivals off in a quarantine tank can greatly reduce the risk of introducing unwanted pathogens to the rest of your fish and aquarium. 


Most hobbyist keep their seahorse aquarium temperature between 70-74 F, cooler than most fish only or reef tanks. Saltwater fish also be kept at this temperature range.

Many fish can handle a wide temperature range. Keeping your temperature consistent is important, quick fluctuations can cause stress. As long as you properly acclimate your fish they should be absolutely fine in this range. In our experience, saltwater fish actually do very well in this temperature range as undesirable bacteria such as Vibrio counts stay lower at cooler temperatures which can possibly help keep your fish healthier, less susceptible to bacterial related issues and less stressed. 

Aquarium Size

One thing to really consider when picking out or planning tank-mates is the size of your aquarium. In general, we recommend a 30 gallon minimum aquarium size for a pair of our larger seahorse species and an additional 15 gallons for every additional pair you wish to keep. 

A frequently asked questions is if you can count sump volume as more gallons for stocking density. You can and it absolutely helps but it is also important to consider larger seahorse species such as H. erectus and H. comes grow to be 5-8+ inches with maturity and need space.

You can easily add a couple peaceful gobies to your without any overstocking issues. If you are planning on keeping a lot of fish or some that you need to be more cautious with keeping it will help to have a larger aquarium where they can have their own space. When fish feel crowded they are a lot more likely to show aggressive behaviors and stress which you do not want in your aquarium. You also want to make sure you are not adding too much bioload to the system with too many fish. Having more hiding places and lots of liverock in the aquarium will also help you tank-mates feel more comfortable.

Fish Size

As a very basic general guideline it best to stick with fish on the smaller size range, such as under ~3 inches. Larger fish are typically going to be more likely to stress or intimidate your seahorses. In addition, these fish are going again be faster eaters in general and may out-compete your seahorses for food. These fish also need more space or territory.

We hope you find this article helpful! If you have any specific questions feel free to reach out to us, 410-618-3604 or email: alyssa@seahorsesavvy.com. We are happy to help and look forward to hearing from you!