How to Care for a Starfish? Are They Easy to Keep? Let’s Know!

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How to care for a Starfish? These are the things you need to keep an eye on

Starfish are really very sensitive creatures. They are very sensitive to their environmental conditions like water pH, water salinity, and their day/night cycle a lot.

All starfish have four basic needs required to survive — water quality, food, light, and water movement. Make sure that you provide them with these in a very balanced way that will be required for their ultimate survival.

The starfish is one of the most sensitive, delicate, eye-catching, and intricate creatures that has made it really very hard for the various marine aquarium enthusiasts to keep them alive.

It is always best to try to maintain their natural type of environment inside the aquarium.

And as, starfish being very sensitive need excellent water quality, and their type of environment inside a reef tank setting so, most people are not always able to sustain them.

And also note that there are about 20 to 50 well-known types of Starfish for Aquariums, and each of these has unique demands and survival care needs that are specific to that type of starfish only.

So, it is always best suggested that you learn a lot about the type of starfish you have in your aquarium from experienced aquarists and fishkeepers.


Here, we’ll show you some of the caring ways that you can follow with almost every type of aquarium starfish in common. However, it is always best suggested that you also learn about that specific starfish type you have along with the following caring tips mentioned below…

So, let’s get started…

1. Maintaining the proper tank conditions at all times

Yes, this is the first step to keep your starfish alive for a very long period. You can do this by maintaining the proper tank conditions at all times just to mimic their sea-type environment in an artificial setup.

The water quality needs to be very clean, stable, and well-established with a water pH between 7.5 to 8.5 respectively. Anyways, 8.2 pH works great.

If you are in the process of setting up a new aquarium, make sure that the new aquarium setup is run for a minimum of 2 to 3 days before the introduction of new starfish.

For the first time you introduce the starfish to your tank it is highly recommended to introduce small amounts of aquarium water into the tank and place the starfish in it for a couple of hours. This will help it to quickly adjust to the tank and adapt itself very well.

Also, make sure to check the ammonia and nitrite levels in the tank until they stabilize at zero before adding more starfish.

One thing you can also do is changing the 25% of water in the tank after every two to four weeks. And, while changing the water, don’t remove the starfish out of the tank.

We must also take care in installing a good pumping and filtration system in the tank. This will aid in keeping the water clean while adding new water to the system after the removal of the previous water,

Also note not to change more than 50% of the water in the tank, because this will remove most of the beneficial bacteria and nutrients cycling there, and can also cloud the tank.

When a new starfish aquarium is set up remember not to touch it and clean it for the initial 2 to 3 days. Let the ecological balance build inside the tank or else, if you choose to overclean it, then it can destroy many beneficial bacteria and upset the balance drastically.

2. Be careful to sudden shifts in water temperature and chemistry of the water tank

We must keep a close eye on any sudden changes in the tank water temperature and chemistry so that it is balanced as per the prescribed requirements.

The water pH must be between 7.5 to 8.5 pH. Anything above or below can cause high stress to the starfish, and so rapid changes in pH should be strictly avoided.

Just make sure to keep the pH constant and stable over the long run.

You will also find Aquarium pH Buffer at your nearest aquarium store. Adding this in prescribed quantity to your water tank can keep the pH of the water stable as more acids or bases get added to the tank over time.

The water temperature must be anywhere between 22°C to 26°C. Starfish are cold-blooded animals and so maintaining this temperature can help them to keep their body temperature constant according to the warmth from their environment.

The tank water salinity should be between 1.022 and 1.025, and the water hardness needs to be around 8-12 dKH specific gravity.

Also, be sure to check the water phosphate levels. High phosphate levels in the water can lead to persistent algae problems and so can cause a high risk to starfish survival.

The optimal phosphate level must be anywhere between 0.05 ppm-mg/l to an upper level of 0.1 ppm-mg/l.

3. Making sure that there is enough room for starfish to move around

A 110 liters capacity water tank will work great for storing anywhere between 1 to 2 numbers of small-sized starfish that are sized anywhere between 4 to 6 inches in diameter as adults.

While for the large-sized starfish that are between 12 to 14 inches in diameter as adults, there needs to be a 300 to 400 liters capacity water tank for keeping each of such starfish.

Starfish are adapted in a way to graze and freely move around whenever it wants, mostly in search of food in the sea bed.

Here, in this case, we must provide them with ample space on the aquarium floor for them to easily roam around

This can only be possible if we maintain more floor space than a wall or vertical space by putting adequate sand inside the aquarium.

Also, we need to make sure about the number of starfish we store in the limited-sized water tank so that they get an ample amount of space for moving around.

4. Following a regular day/night cycle around the tank

We all must know that starfish have “eyespots”, one at the tip of each arm. These eyespots are sensory cells that contain various light-sensitive pigments which help the starfish to detect shadows, light density, and also to adapt to the various changes as per the brightness level of light.

They use their eyespots to navigate in their surroundings. Thus allowing them to hunt for more food and hide from predators as per the diurnal light routine.

So, it is a must that we follow a regular day/night cycle around the tank. We can do this by keeping the starfish tank under light for 10 hrs, 10 hours in no light or very dim light condition, while the other 4 hrs of the day in low power LED light to mimic the moonlight-type feeling.

However, to make the starfish feel like daytime, you can keep the tank in a sunlight-falling room and this will work great. But, make sure that you don’t keep the tank in direct contact under the heat and sunlight falling directly over it.

5. Making sure that there are lots of hiding places for them inside the tank

Following the day/night cycle, most starfish tend to stay hidden inside the various pieces of stuff that are kept inside the tank.

So, we must make sure that there are lots of hiding places for them inside the tank. This will help them to feel secure by hiding as per their daily routine.

They can be also seen digging inside the sand in the tank by burrowing and tossing sand over their bodies.

They can be also sometimes seen coming out of their hidden places, grabbing their food, and then moving back to their hiding places to feast.

You can put pieces of rocks, pebbles, small aquatic grasses and plants, tubes, pipes, blocks, etc. for them to hide happily.

Actually, the main reason for maintaining the hideout places for starfish is that it will help them stay safe and feel protected when they are uncertain, frightened, stressed, or uncomfortable.

So, keeping an eye on this can help you to have a safe place for them to relax, retreat, feel comfortable, and secure. And so, this will in turn, greatly improve a starfish’s chances of survival in the tank.

It is also to be known that while in an aquarium starfish are rarely at risk to be killed by predators so they may hide at various instances like when they are introduced to new aquarium species, or to a new unfamiliar territory, out of loneliness, various environmental changes, day/night cycle, overcrowding, and sickness.

6. Maintaing a balanced diet is important to keep them healthy

While in the wild, starfish are known to feed by scavenging and by almost eating anything they get ranging from fish poops to algae to various other small fishes, insects, worms that comes their way.

But, while in the aquarium it is not always right and possible to provide them with such a kind of diet. So, we must make sure that they get a balanced diet which is very important to keep them healthy.

We can add pieces of fish foods, small chunks of meat, fish, or vegetables to their diet. They can also eat fish flakes, and also pellets of other aquarium species that are there in the bottom of the tank.

You can also feed them with chopped snails, clams, shrimps, and mussels by simply putting these inside your tank, and they will be happy to feed on as per their routine.

They can also feed on the little algae, micro-organisms, detritus, leaves, and water insects if any that they will find while grazing on the rocks, sand bottom, and other pieces of stuff that you have kept inside the tank.

While feeding it is always recommended that you don’t feed them by holding them with your hand. They are sensitive creatures and doing so may lead them to fall under stress and so risking their lives over time.

7. Introducing them to peaceful and calm tank mates in the water tank

It is to be noted here that not all starfish aquarium species are reef and fish safe. And, those starfish that are considered reef and fish safe are not 100% completely reef and fish safe marine creatures.

Reef and fish safe are referred to those aquarium creatures that don’t normally feed on the fishes and small invertebrates that can be found in the water tank artificial reefs or natural reefs that are made up of rocks or the skeletons of small animals called corals.

Popular examples of reef and fish safe starfish include Red Linckia Starfish, Sand Sifting Starfish, Banded Serpent Starfish, and Brittle Starfish.

While some of the popular examples of reef and fish unsafe starfish include: Red Knobbed Starfish, Chocolate Chip Starfish, Purple Linckia Starfish, Asterina Starfish (with caution), and Green Brittle Starfish (with caution).

Be careful while placing starfish like the Asterina Starfish and Green Brittle Starfish in your tank as mentioned with the term “with caution” within brackets. They may sometimes cause a threat to your aquarium life as they may rarely act predatory and may decide to dine on clams, other starfish, coral, and more that you want to keep in your tank.

It is recommended that you only keep the reef and fish safe species of starfish in your tank with other species of fishes and small invertebrates. As, they will only feed on the bacteria and algae that naturally grow on rock surfaces, glass walls, gravels, or on the sand.

While on the other case, it is not at all recommended that you keep any reef and fish unsafe species of starfish in your tank with other species of fishes and small invertebrates. They are known to be aggressive feeders and so can feed on anything that includes soft corals, sponges, other starfish, worms, clams, and even on the fishes like silversides.

8. Caring for any sick starfish you have inside the tank

If you have maintained all of the water salinity, hardness, pH level, and have also changed the tank water at regular intervals of at least two weeks time period, and also that you have not over cleaned your water tank, then chances are very good that your starfish will be disease-free.

Instead, you should also keep a close eye on your starfish even after maintaining all such mandatory conditions as prescribed by your aquarium expert.

If in case there is a rare cause of disease then you must remove the starfish or call an expert to help you over.

You can also look at the starfish for any kind of black or white spots or fungus, color fading, twisted arms, white lesions, deflation of arms and body, arm loss, and body disintegration. If you see such things then chances are very high that your starfish is sick.

Also that a sick or near to death starfish will not be so active and healthy and may show a partial absence of reaction to stimuli. If such a thing appears, then call your aquarium expert as soon as you can.

A recently discovered starfish disease is the Starfish Wasting disease. Starfish Wasting disease is also called Starfish Wasting Syndrome and it is characterized by showing abnormally twisted arms, white lesions, deflation of arms and body, arm loss, and body disintegration in the starfish, causing mass mortality to those affected ones.

Can you keep starfish from the ocean as a pet?

First of all, not all species of starfish can be taken out of the ocean and can be kept as pets. Special care needs to be taken by an experienced keeper if they try to do so, but only with a few countable starfish species.

There are nearly about 50 starfish species that can be kept as pets and some of the best examples are Sand Sifting Starfish, Banded Serpent Starfish, Brittle Starfish, Chocolate Chip Starfish, and Red Knobbed Starfish.

And, it is not so easy to care for starfish in an aquarium if you don’t know anything about their mandatory needs and basic requirements.

So, it is always best suggested that you first learn theoretically about it, and then you should start rearing them in your tank to gain live experiences about keeping them.

Starfish are the keystone species that have made them adapt so well to their ecosystem. These predatory invertebrates can impactfully keep in check and prevent other species like mussels, barnacles, limpets, small fishes, worms, etc. from taking over the marine ecosystem.

By doing so, Starfish (Sea Star) helps ensure healthy populations of seaweeds, and thus directly or indirectly promote the sustainability and growth of other marine communities that feed on the seaweeds.

It has been known that they eat basically anything that comes across their way. Their this kind of feeding activity controls the whole ecosystem and aid in maintaining the marine ecosystem in the oceans.

So, it is not always a great choice to keep them in artificial ecosystems that are maintained inside an aquarium, as it is rare that they will sustain well in the aquarium while following their respective ecological niches due to the lack of resources.

However, there are a few species like those mentioned above that can survive well if we just fulfill their mandatory requirements and basic needs by trying to mimic a little to more of their kind of marine ecosystem in the water tank artificially.

Can starfish live in freshwater? What do you think?

No starfish can live in freshwater. Almost the majority of the starfish species are saltwater creatures living in the ocean and seas, while a few of the starfish are capable of living in brackishwater (briny water) having more salinity than freshwater, but not as much as seawater.

There is no chances of survival for a starfish in freshwater. However, a few species can stay in brackishwater but not for a longer period of time or else they will soon die.

However, there are a few species like Asterias rubens (common starfish) that can live in brackishwater during their lifetime. they have well-adapted to do so.

Seawater includes the water in oceans and seas, while brackishwater (briny water) includes those water that can be seen in the conjunction areas of freshwater and seawater like estuaries, mangrove swamps, and salt marshes.

While, freshwater is found in glaciers, lakes, reservoirs, ponds, rivers, streams, wetlands and even in groundwater. However, there is no chances for any species of starfish known so far to survive in freshwater of any kind.

Starfish can’t survive in freshwater because their cells have a very high concentration of salt inside. So, if starfish are kept in freshwater then the water from the surroundings will likely flow inside their body cells and will start to accumulate there due to the process of osmosis.

As a result, their cells will get hypotonic in nature making the cells bloat and burst out because water keeps flowing in to dilute the cells’ solution. So, this can ultimately cause death to the starfish if kept in fresh water for a longer period of time.

Also, that seawater is very much essential for them in order to use their waster vascular system functionality in order to move, locomote, for feeding and waste removal purposes, and also for heir respirational needs. The seawater composition plays a key role in this functioning of the waster vascular system.

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