Fish compatibility - HELP!!!

[Thomas Cummins]

I am in a marine biology class in high school and we have our own fish tanks. At the start of the school year (late August), we originally chose a tall, cylindrical tank that seems like it was designed for jellyfish. We had 3 fish in there - a yellowtail blue damsel (1.5 in), a sergeant major damsel (1 in), and a high-hat. We were originally concerned about the aggression of the damsels towards the high-hat but all 3 fish were surprisingly peaceful towards each other. However, since we couldn't reach the bottom of the tank, we had lots of trouble delivering food to the bottom-feeder high hat and it died.

After red algae started growing in our tank and some invertebrates died, we finally decided to ditch the cylindrical tank and transfer the fish to a 30-gal tank (which has been up for about 1.5 weeks). Our yellowtail and sergeant major are now in there and it is FAR easier to feed them and take care of the tank.

In the next 2 weeks we are getting a new shipment of fish and we get to choose which kinds we want. The first thing I am considering is the green chromis damsel. My teacher suggested we order 3 of them. I also am interested in the royal gramma, firefish goby and tailspot blenny, and I want to get 1 of the 3, but I am worried about their compatibility with the other 2 damsels. I know damsels are notorious for their aggression, but the 2 in our tank have been surprisingly peaceful, although I'm not sure whether it's because they're both damsels (but they were good towards the high-hat before it died). I am also not sure how many fish is too many - would the 2 damsels+3 chromis be too much already, or would one other fish be okay? We have just a bit of live rock on each side in our tank and the yellowtail uses one side as a hiding place. We also have a small snail in our tank. Between the 3 fish I'm considering (not including the chromis), I want a semi-hardy fish since my marine bio group is beginners and because our access to the classroom is limited, but I'm just unsure of how the damsels will act towards them. I don't care much about whether they're carnivorous, herbivorous, etc. since we can now feed them a lot easier.

 

[Thomas Cummins]

I am in a marine biology class in high school and we have our own fish tanks. At the start of the school year (late August), we originally chose a tall, cylindrical tank that seems like it was designed for jellyfish. We had 3 fish in there - a yellowtail blue damsel (1.5 in), a sergeant major damsel (1 in), and a high-hat. We were originally concerned about the aggression of the damsels towards the high-hat but all 3 fish were surprisingly peaceful towards each other. However, since we couldn't reach the bottom of the tank, we had lots of trouble delivering food to the bottom-feeder high hat and it died.

After red algae started growing in our tank and some invertebrates died, we finally decided to ditch the cylindrical tank and transfer the fish to a 30-gal tank (which has been up for about 1.5 weeks). Our yellowtail and sergeant major are now in there and it is FAR easier to feed them and take care of the tank.

In the next 2 weeks we are getting a new shipment of fish and we get to choose which kinds we want. The first thing I am considering is the green chromis damsel. My teacher suggested we order 3 of them. I also am interested in the royal gramma, firefish goby and tailspot blenny, and I want to get 1 of the 3, but I am worried about their compatibility with the other 2 damsels. I know damsels are notorious for their aggression, but the 2 in our tank have been surprisingly peaceful, although I'm not sure whether it's because they're both damsels (but they were good towards the high-hat before it died). I am also not sure how many fish is too many - would the 2 damsels+3 chromis be too much already, or would one other fish be okay? We have just a bit of live rock on each side in our tank and the yellowtail uses one side as a hiding place. We also have a small snail in our tank. Between the 3 fish I'm considering (not including the chromis), I want a semi-hardy fish since my marine bio group is beginners and because our access to the classroom is limited, but I'm just unsure of how the damsels will act towards them. I don't care much about whether they're carnivorous, herbivorous, etc. since we can now feed them a lot easier.

BTW, I'm open to other fish too if they are get along with the others, but we are on a budget so I'm trying to keep them $20 or under.

 

[Florida Sunshine]

What kind of filtration do you have on the tank and what is your maintenance routine? Do you regularly check your water parameters and do water changes?
IMO you are pushing it on your stocking limit if you add the 3 chromis but with proper care it could be possible.

 

[Thomas Cummins]

We have the Tetra Whisper Internal Power Filter. Every Friday we do a 5-10 gallon water change, and afterwards do tests on pH, salinity, ammonia, nitrate, nitrate, calcium, temp., and phosphate. We could always do 1 chromis and put other types in, but my teacher said the otherdamsels might be better with the chromis if they are in a group of 3. We also have some fake plants in there and a plastic lighthouse for decoration, so we would probably have to take some things out if we get more fish.

 

[MSB123]

I would increase your water change schedule to 50% once a week, or 30% twice a week. Do you have a protein skimmer or a reactor? or are you just running this with as minimal stuff as possible? I would suggest getting 1-2 Chromis and maybe a lawnmower blenny or a tailspot blenny for algae.

 

[MSB123]

We have the Tetra Whisper Internal Power Filter. Every Friday we do a 5-10 gallon water change, and afterwards do tests on pH, salinity, ammonia, nitrate, nitrate, calcium, temp., and phosphate. We could always do 1 chromis and put other types in, but my teacher said the otherdamsels might be better with the chromis if they are in a group of 3. We also have some fake plants in there and a plastic lighthouse for decoration, so we would probably have to take some things out if we get more fish.

also, which school are you at?

 

[Thomas Cummins]

Fauquier HS in Northern VA. We don't have a protein skimmer or anything, we pretty much use what we're given since it's a classroom setting. But the teacher might have a protein skimmer if I ask.

 

[MSB123]

Alright, I would ask him/her for one, it would allow for a larger bio-load. Also ask if they have any sort of cycled filtration media that you can use, it will greatly increase your nitrifying bacteria.I have an extra protein skimmer that I can send you for free if the teacher doesn't have one. Its a hang on back fixture.

 

[MSB123]

it looks like this

 

[Humblefish]

Honestly, the damsels need to go before adding more fish. At least the Sergeant Major; the Yellowtail may be a little more hit or miss in a 30 gal.

They may be OK with one another (for now), but I would anticipate aggression towards any new additions.

 

[Thomas Cummins]

Ok I'll talk to him about it. We also wanted to add in a brittle starfish for cleaning, would that be too much?

 

[MSB123]

what are the dimensions of the tank? In my experience, brittle stars like a lot of room to move around. if it is under 30" by 30" floor space, I would suggest a sand sifting star. I have 3 in my 150 and they are really efficient at turning over my sand and eating detritus.
https://www.saltwaterfish.com/product-sand-sifting-starfish

 

[sfin52]

Damsels become extreme but heads for lack of a better description. I had 3 Humberg that where torturing my lion fish. They had to go.
@MSB123 sand sifters need a mature tank with a deep sand bed I could be totally wrong. ;Nailbiting

I second a skimmer

What is the power filter rated for. You may need a bigger filter as well or a second.

Bird course I hate treating homes with fleas. I always leave with a few on me. Reminder don't leave home with out deep woods off. Now I've got to treat my truck. Back to topic.

A 30 gallon is going to limit your fish numbers and the type you put in there.

The smaller clowns like the perc or oscul may be a good fit. They are hardy and not as aggressive. Not sure how they will act in a 30gallon. I don't think they will be able to go with the royal. (Somebody please correct me if I'm wrong)
Is this tank going to be a reef? Also limits options. Good luck.

 

[Thomas Cummins]

what are the dimensions of the tank? In my experience, brittle stars like a lot of room to move around. if it is under 30" by 30" floor space, I would suggest a sand sifting star. I have 3 in my 150 and they are really efficient at turning over my sand and eating detritus.
https://www.saltwaterfish.com/product-sand-sifting-starfish

Turns out there is actually no live rock in the tank. All dry rock. Not sure if this limits or opens up more possibilities. I will figure out the dimensions over the weekend.

 

[Maritimer]

Gonna agree with Humblefish here - yellowtails are probably one of the feistier damsels in their family, but still on the mellower side for damsels in general. I've got azures and talbott's in the same family, and love 'em.

Sergeant-majors, on the other hand, are rugged - and get pretty darned big for a damselfish. You'll be happier, long-term, if you find a bigger home for that fellow.

Green chromis can be charming, but have a problem with a disease called Uronema marinum. Even when they don't, many folks report them picking the weakest off, until there's only one.
The royal gramma would spend most of his time close to his favorite bolt-hole in the rock, and will follow the contours of the rockwork - even to the point of swimming upside-down.
The firefish would hover in open water - though never more than a fraction of a second from safety - awaiting drifting plankton.
The tailspot blenny will snuggle into holes on the rock and watch the world go by, periodically nipping out to nip at algae - or the food you offer.

All delightful fish, to my eye.

The brittle star, if not huge, will snuggle into a crevice, extending an arm during the day or emerging at night to prowl for food.
The sand-sifting star, in a tank that size, may consume all of your sand microfauna fairly quickly - and then starve.

~Bruce

P.S. - Welcome to Reef2Reef, Thomas!

 

[Thomas Cummins]

Damsels become extreme but heads for lack of a better description. I had 3 Humberg that where torturing my lion fish. They had to go.
@MSB123 sand sifters need a mature tank with a deep sand bed I could be totally wrong. ;Nailbiting

I second a skimmer

What is the power filter rated for. You may need a bigger filter as well or a second.

Bird course I hate treating homes with fleas. I always leave with a few on me. Reminder don't leave home with out deep woods off. Now I've got to treat my truck. Back to topic.

A 30 gallon is going to limit your fish numbers and the type you put in there.

The smaller clowns like the perc or oscul may be a good fit. They are hardy and not as aggressive. Not sure how they will act in a 30gallon. I don't think they will be able to go with the royal. (Somebody please correct me if I'm wrong)
Is this tank going to be a reef? Also limits options. Good luck.

Do you think leaving the yellowtail damsel in and taking out the sergeant major would be okay? It’s so hard to tell how they are around other fish- they lived with a high hat and surprisingly got along fine, but he didn’t last long thanks to our previous tank. I can’t believe how peaceful they are around one another, especially since all I read is how aggressive sergeant majors are. The sergeant major is very small and he hasn’t grown much at all since we got him, believe it or not - we think the strange tank we had before the current one might’ve made it more difficult to grow (another group in our class got the same fish, same size on the same day from the same company, and it has grown substantially bigger than ours).

My teacher does have a skimmer and we will hopefully install that soon. Turns out we only have dry rock in our tank, and it’s a very new tank so no bacteria has grown on the rocks or anywhere yet.

How about fish like the purple pseudchromis, tailspot blenny or six-line wrasse? I’m not sure whether to go with a fish that can fight the damsels back or a fish that would stay away from them. I’m open to others, just not sure who would get along with who. The compatibility chart seems to mean nothing when we have damsels in our tank. We could possibly get clownfish but we’re on a tight budget ($60 per classroom tank) and ordering everything from saltwaterfish.com and I think they’re a bit more expensive or only come in groups. The green chromis are very cheap so I liked the idea of having a group of 3 of those.

The yellowtail has established a corner of the tank under the rock as his hiding spot, but the sergeant major swims basically everywhere, specifically the top of the tank (he always wants food).

I’ll look in to a clean-up crew, but is it as crucial in a fish-only tank with a few rocks? We have a nassarius snail and 2 green urchins but I was looking at the possibility of a few hermit crabs, along with a brittle or sand sifting starfish. But I know it’s a smaller tank so I can’t do all that much.

 

[sfin52]

The problem with damsels is that as they get bigger they get more aggressive. I would return them to the lfs if possible.

To help with cycling I would add some bacteria to the tank. I use stability by seachem.
With the ur urchins make sure your rock work is secured they will topple it.

I would stay away from a six line but fairy wrasses may be good.
If you have a lfs I would use them. They may be bit more expensive but there is no shipping. They maybe able to do some type of trade for the damsels as well. Sargent majors get large and about 6 inches.

With 30 gallon tank stay with the smaller fish. Royal gram. Clown stuff like that. Can have more fish.

 

[sfin52]

Also a black brittle would be fine in a 30. Mine never leaves the rock he is in

 

[Thomas Cummins]

Gonna agree with Humblefish here - yellowtails are probably one of the feistier damsels in their family, but still on the mellower side for damsels in general. I've got azures and talbott's in the same family, and love 'em.

Sergeant-majors, on the other hand, are rugged - and get pretty darned big for a damselfish. You'll be happier, long-term, if you find a bigger home for that fellow.

Green chromis can be charming, but have a problem with a disease called Uronema marinum. Even when they don't, many folks report them picking the weakest off, until there's only one.
The royal gramma would spend most of his time close to his favorite bolt-hole in the rock, and will follow the contours of the rockwork - even to the point of swimming upside-down.
The firefish would hover in open water - though never more than a fraction of a second from safety - awaiting drifting plankton.
The tailspot blenny will snuggle into holes on the rock and watch the world go by, periodically nipping out to nip at algae - or the food you offer.

All delightful fish, to my eye.

The brittle star, if not huge, will snuggle into a crevice, extending an arm during the day or emerging at night to prowl for food.
The sand-sifting star, in a tank that size, may consume all of your sand microfauna fairly quickly - and then starve.

~Bruce

P.S. - Welcome to Reef2Reef, Thomas!

Thank you for all the info! I just realized we have a tank with no live rock. It’s all dry rock and not a whole lot of it. Enough hiding places for probably 2 more fish, but we can add in more rock if we have to. I’m guessing this probably eliminates the fire fish possibility since they’re mostly reef fish. Assuming I got rid of the sergeant major and we have only the yellowtail in there, what would you suggest putting in our 30-gal tank? It is also a 1.5 week-old tank so I’m not sure how many fish that rules out.

 

[sfin52]

Slow down. It's a week old. Give it time to adjust to the fish and the fish waste. Dead rock and not cured rock could cause issues. Watch the ammonia and nitrite. They may spike. If they do be ready for a water change asap. I recommend bacteria in that tank to help avoid a large cycle.