Thank you Sir ! I will do the seperate post. I have posted on forums maybe 5 times in my life haha
Welcome!
Saltwater is definitely a bit different from freshwater, but it’s very learnable—especially with a strong community like this one. I made the same transition after years in freshwater, and I ended up enjoying saltwater even more. Make sure to always top off with RODI water as well as when the system evaporates the salt stays to avoid a bad salinity swing!
As for the fish, I don’t think you need to get rid of
all the fish immediately. That said, there are a few I would strongly consider moving, trading, or surrendering to a local fish store sooner rather than later for your benefit, and I’ll explain why below.
Disease & Nutrient Load
All saltwater fish carry parasites and disease naturally. Stress is what turns those into real problems. Overcrowding, limited swimming room, and unstable water quality all increase that risk & actually will cause the diseases to spread to all the fish crashing the system so that is a major concern.
Large fish in a small system also mean heavy nutrient production. Without frequent, fairly large water changes (or strong filtration), nitrates and phosphates rise quickly—leading to fish & coral stress, algae, dinos, or cyanobacteria, all of which can negatively affect both fish and corals. Many of those fish are less than a year old as well and will reach full size in a year or two max so I think he may have not been 100% honest when selling you the tank as for how long he had it or how long he has had those fish.
Blue Hippo Tang
The biggest concern is the Blue Hippo Tang. Unfortunately, they stress very easily and are extremely prone to ich. While freshwater fish tank size recommendations are often exaggerated, saltwater fish recommendations especially around tangs are one of the exceptions. Most reputable sources list 180 gallons for hippos, and even if that’s generous, a 55-gallon tank is still far too small & the reason is not that the fish will die but that before that it will get stressed likely get Ich & spread it to every living fish in the system. (More Below)
When a tang becomes stressed—due to limited swimming space or lack of algae—it often develops ich, which can spread rapidly and wipe out an entire tank. They also require constant grazing (algae/nori), grow very quickly, and struggle without a well-established system. A smaller tang like a Tomini is usually considered a 75-gallon minimum, and even then it’s best added to a well-established tank (typically over a year old).
Niger Trigger
The Niger Trigger is another fish I’d strongly recommend rehoming. These fish really belong in 180+ gallon systems and can become aggressive in smaller tanks. In confined space they can easily stress or outright kill tankmates. They’re also not coral-safe, so if your long-term goal includes corals, this fish will be an issue. Amazing fish—but not a good fit for this size system.
Blue-Spotted Puffer
The blue-spotted puffer
may eat coral—some behave, others don’t. If your goal is a coral-heavy reef, this is something to be aware of. If it starts picking at coral, removal is the only solution. That said, it could work very well in a FOWLR (fish-only with live rock) setup.
Chocolate Chip Starfish
Chocolate chip starfish will 100% eat coral eventually. If you care about keeping coral long-term, I would remove it. If not, it can stay. If you want a starfish that’s reef-safe, some bristle stars can be a better alternative—but a starfish isn’t required at all.
Overall System Thoughts
The remaining fish should be fine. I’ll be honest though—the system looks very young and likely under a year old. Saltwater tanks rely heavily on live rock and sand for biological filtration; far more than freshwater systems. Most modern reefs use sumps or AIO setups to provide high water movement and oxygenation. Hang-on-back and canister filters aren’t commonly used in reef systems because they’re not ideal for nutrient control long-term & beneficial bacteria does not live as much in the filter but more on the live rock & sand in the tank. Looking at the tank you probably need a good amount more of live rock in the system.
If you choose to keep all current fish, a protein skimmer will likely be necessary, or you’ll need a very aggressive water-change schedule. You can also get different fish to replace the old fish as well & it may still not require a skimmer. I am 27 and definitely do not have the same financial abilities as some on here so I understand the struggle of balling on a budget! The key is to not lose hope & it would not shock me if some stores would trade the fish you have in for credit or even other fish more suited for that size of tank!
For salinity measurement, I recommend either:
- A Tropic Marin hydrometer (very reliable), or
- A refractometer (Amazon is fine—just make sure it’s calibrated properly)
You’re off to a good start, and with a few adjustments now, you’ll save yourself a lot of frustration later.
