Pot Bellied Seahorse

Dear Ross:

Yes, sir, I do feel that potbelly seahorses (Hippocampus abdominalis) would not do well in a 20-gallon aquarium. The water temperature in your seahorse tank would be excellent for potbellies, but they definitely need a little more room to roam as they grow, sir.

As you know, Ross, H. abdominalis is the largest and most massive of all the seahorses. The largest specimens can grow to over 14 inches (35 cm) in length, and most pot bellies reach an adult height of 7-10 inches (18-25 cm).

In addition to their size, potbellies are also the strongest swimmers of all the seahorses and among the most active of all the Hippocampines. As an example, while other seahorses are feeble swimmers that seldom stray far from home, H. abdominalis is a strong swimmer that ventures far and wide. Most hippocampines are strict homebodies — real stick-in-the-muds that are tied to a relatively small home base. Hence researchers refer to them as site-faithful, meaning that divers find them day after day with a few feet of the same place on the substrate, as demonstrated by tagging studies that followed individual seahorses for an entire breeding season. But not abdominalis; compared with its conservative cousins, Big Belly Seahorses are footloose and fancy free — regular nomads that can stand up to a stiff current and often travel hundreds of yards every day.

The dorsal fin of H. abdominalis is proportionally the largest of any seahorse that=s been studied thus far, and this outsized "propeller" makes it a relatively powerful swimmer. Neil Garrick-Maidment notes that temperate seahoses, in general, tend to have bigger dorsal fins in proportion to their size than their tropical cousins, and speculates that this may be due to their need to cope with stronger currents and to travel further in search of food. So the combination of large size and strong swimming ability means that these king-sized Clydesdales would be cramped in a 20-gallon aquarium.

I would only consider trying potbelly seahorses if you are willing to start with a young specimen and are prepared to relocate it to a larger aquarium as a matures.

But there are other temperate seahorse species that are smaller and would make great tankmates for your Zulu in a 20-gallon aquarium, sir. For example, the short-snouted seahorse (Hippocampus breviceps) and the Sydney seahorse (H. whitei) would do great in a setup like yours, if you can locate any specimens here in the US. If you contact me off list ([email protected]), I will be happy to provide you with lots of detailed information on both of these temperate seahorse species.

It’s great to hear that your original Zulu Lulu (H. capensis) is continuing to thrive after two years in your aquarium, Ross, but unfortunately it’s not possible for Ocean Rider to accept the return of your Zulu even free of charge because they are a High-Health aquaculture facility. High Health certification is very difficult to achieve, which is which OR is the one and only seahorse farm to be awarded High Health status. In order to earn High Health Certification, an aquacultural facility must first prove that it enforces a strict biosecurity program with rigorous quarantine protocols, and that at no stage in the breeding and rearing process are its livestock ever exposed to open systems or wild-caught seahorses, and that they never come in contact with seahorses from other breeders or sources. So if they brought back your Zulu Lulu, it would have to be kept in quarantine, permanently isolated from all of the other seahorses. It could not be used as broodstock and they could not sell the pony to other hobbyists, which would be a violation of their High Health certification. Your Zulu could only be used as a display specimen, in a tank of its own, devoid of other seahorses, which is just not feasible for obvious reasons.

But there are quite a number of other colorful specimens that would try in a temperate tank like yours that you can consider, sir. Here’s some information on temperate tankmates excerpted from my new book (Complete Guide to the Greater Seahorses in the Aquarium, unpublished) that should be suitable companions for temperate seahorses such as H. capensis, H. abdominalis, H. whitei or H. breviceps:

Temperate Tankmates.

In general, tankmates for temperate and subtemperate seahorses must meet the same compatibility requirements as the companions for tropical seahorses, with of course the added proviso that they must be comfortable at cooler temperatures. Coldwater seahorses (temperate and subtemperate species) generally tolerate temperature ranging from 50 – 70 degrees F (10-21 C; Kuiter, 2000), with 60-66 F (16-19 C) being a reasonable range for subtemperate aquariums and 66-72 F (19-22 C) a feasible temperature range for temperate species (Wrobel, 2004). These cooler temperature requirements restrict the suitable tankmates for coldwater seahorses severely. Temperate fishes and invertebrates are simply much less readily available in the US than tropical species. Nevertheless, there are a number of specimens that make delightful tankmates for temperate and subtemperate seahorses.

Chief among these are the gaudy Catalina gobies (Lythrypnus dalli). These little jewels will thrive at temperature from 64-72 F (18-22C) and are perhaps the most colorful of all the gobies with their dazzling blue and orange stripes (Wrobel, 2004). Beautiful, peaceful, and passive eaters, Catalina gobies are the ideal tankmates for coldwater seahorses. Best of all, they are widely available from pet dealers.

Although they are hard to come by here in the US, Australian hobbyists with temperate tanks report that the humble Hulafish (Trachinops taeniatus) does well in cool water tanks with temperate seahorses such as pot bellies (Hippocampus abdominalis). It is a shy, passive fish sometimes displayed in public aquariums.

A number of colorful coldwater invertebrates are also available for temperate tanks. For example, Bat Stars (Patiria miniata) are very common denizens of the kelp forest and tide pools in temperate seas, and they are brilliantly colored with variegated patterns of vivid red, orange, violet and beige (Wrobel, 2004). They are active scavengers but not as voracious as some of the predatory starfish, making them good candidates for a seahorse-only setup. However, they cannot be trusted in a modified reef tank with soft corals and sessile invertebrates (Wrobel, 2004). Although they will scavenge for meaty leftovers such as frozen Mysis, for best results they should be fed a piece of fresh fish or shellfish about once a week. You will know when it’s time to offer them a meaty tidbit since they will climb the glass and expose their tube feet and underside at the surface of the water when hungry and searching for food (Wrobel, 2004).

Bloodstars (Henricia sp.) are another good choice for a temperate tank (Wrobel, 2004). Despite their ghoulish name, which refers to their coloration, these starfish are entirely innocuous in the aquarium. Their diet consists primarily of detritus and small organic particles that adhere to their mucous coat and are passed along to their mouths when enough has accumulated (Wrobel, 2004).

Most other coldwater starfish should be shunned. For example, the beautiful Rainbow Stars (Orthasterias koehleri) are predatory on mollusks, as are Ochre and Giant-spined Starfish (Pisaster sp.; Wrobel, 2004). Although lovely, their mission in life is to terminate marine mollusks. They pose a serious threat to tank inhabitants, and they will relentlessly hunt down and devour all the snails in your cleanup crew (Wrobel, 2004). They can’t be bargained with or reasoned with. They don’t know pity or mercy or fear. And these gastropod terminators absolutely will NOT stop — ever! — until all your snails have been consumed. Avoid them accordingly.

Worse yet are the attractive Sunflower Stars (Pyncnopodia helianthoides; Wrobel, 2004). With more than 20 arms, these starfish are capable of surprising speed and should be considered heavily armed and dangerous (Wrobel, 2004)! Day and night, the activities of these malicious, multi-legged monsters are one endless search-and-destroy-mission for sessile invertebrates and anything else the can overpower. Aside from their destructive habits, they are notorious for releasing toxins into the water (Wrobel, 2004).

Coonstripe Shrimp (Pandalus danae) are ideal for a temperate aquarium (Wrobel, 2004). Brilliantly colored, these dazzling shrimp are boldly marked with electric blue and red patches (Wrobel, 2004). They will seek out crevices, caves, overhangs and other sheltered nooks and hidey-holes in the aquarium, and if you can get large enough Coonstripes they should do very well with temperate or subtemperate seahorses.

There are also a number of coldwater snails that make valuable additions to the temperate tank. Like their tropical counterparts, temperate turban snails are prized for their ability as algae grazers. The Red Turban (Astraea qibberosa) is renowned for its tireless efforts to cleanse rocks of stubborn filamentous algae and brown diatom growths (Wrobel, 2004). An armored brigade of these snails can do wonders for controlling nuisance algae in a temperate tank. The common Tegula tide-pool snails will perform a similar service in temperate tanks, and their small size allows them to get in tight spots where the Turbans cannot go, making a mixture of temperate Astraea qibberosa and Tegula snails a very effective combination for combating invasions of nuisance algae (Wrobel, 2004).

Most temperate snails are rather drab, but the omnivorous top shells (Calliostoma sp.) include a number of colorful species such as the Jeweled Top Snail, which is decorated with gold and purple spiral bands (Wrobel, 2004).

If your coldwater tank is setup for temperate species, with a milder temperature range of perhaps 68-72 F (20-22 C), then you have many more options. Virtually all of the hermit crabs, snails, and cleaner shrimp that are commonly keep in tropical tanks will adjust very well to those temperatures (Leddo, Jun. 2003). Likewise, almost all of the commonly available gorgonians, feather dusters and brittle stars are comfortable within that range of temps (Leddo, Jun. 2003).

Among the soft corals, the following species are suitable for an aquarium with temperatures 68-72 F or 20-22 C (Leslie Leddo, pers. com.):

Tree Leathers (Cladella sp.) 68-79 F (20-26 C)
Mushroom or Cup Leather Coral (Sarcophyton glaucum) 68-79 F (20-26 C)
Lobed Leather Coral (Sinularia dura) 68-79 F (20-26 C)
Kenya Tree (Lemnalia africana) 68-84 F (20-29 C)
Broccoli Soft Coral or Tree soft coral (Capnella sp.) 68-84 F (20-29 C)
Pinnate Bouquet Soft Coral (Anthelia glauca) 68-84 F (20-29 C)
Lobophytum sp. 68-86 F (20-45 C)

Among the fishes that may do well in a temperate setup are the Yellow Coral Gobie or Yellow Clown Gobie (Gobiodon okinawae, 68-77 F), Wheeler’s Prawn Gobie (Amblyeleottris wheeleri, 69-86 F), the Neon Gobie (Gobiosoma oceanops, 70-82.5 F), the Pinkbar Gobie (Amblyeleottris aurora, 70-82.5 F), and the Yellow Snout Gobie (Stonogobiops xanthorhinica, 70-81 F) (Leslie Leddo, pers. com.).

Best of luck livening up your seahorse tank with some other colorful tempered specimens, Ross!

Respectfully,
Pete Giwojna