Some questions regarding fish death and guidance

[amoeba2006]

Sorry in advance for this extremely long post. So for some context, I am from India. Saltwater aquariums are not at all popular here, so I have no local lfs that can help me out. I have had 10 years of experience in the fresh water hobby, and am looking to transition into saltwater.

I had setup a small 60 litre ( approximately 15 gallon) saltwater tank at the beginning of December 2024. It was a fish-only tank ( with white aragonite sand and dead rocks). I had asked my local supplier for some guidance, and he suggested that I can keep up to 4 fishes in the tank, and because I am a total noob...I managed to make all the wrong choices.

I got 1 percula clownfish, 1 juvenile blue tang , 1 juvenile saddleback clown, and 1 juvenile Centropyge bicolor angelfish. ( Later I did some proper research and I figured out I had been completely misled...and I had the blood of 4 fish on my hands). The clean up crew consisted of 1 blue legged hermit crab and one snail ( I don't know the exact species..I just found one in the beach and took it back home) .

I had added some saltwater nitrifying bacteria ( from some local brand) ( it was supposed to work in both freshwater and saltwater conditions). I had used Red Sea marine salt..and striclty maintaiend salinity at 35ppt . I used to top of with dechlorinated water daily. My supplier gave me some test strips and said that they were enough. After ghost feeding the tank for 1 week , I saw a 10 ppm of nitrate reading on the test strip and contacted the lfs. They said my tank was set and I got the four fishes mentioned above.

Initially everything was going fine for like 3 weeks ( other than the fact that the angel was not eating), ( I tried feeding it algae flakes, with garlic extract ...some brine shrimp flakes..and even pellets)..It simply would not eat.
After 3 weeks, suddenly the angel became lethargic and would go down towards the sand bed. We had given up hope that it was going to survive at all..as it had not been eating
.Soon the saddleback clown passed away..it would move down towards the sand bed and lay there ( I was surprised, because it was a very active fish..would take food regularly) ...
Then the angel followed. After the angel passed away..after 3 days the tang would gradually start showing the same symptoms ( the percula clownfish was doing fine).

The local guy asked me to get my nitrate checked using a salifert test kit..it was 10 ppm ( again). Then he said things like it is impossible to run a saltwater tank without a sump, protein skimmer. My power filter was not sufficient ( it was 800lph), it is impossible to create a saltwater tank in 15 gallons..and he totally backed off from helping me..saying I needed a better tank and asked me to cough up almost 1800 usd ( in local money) for a better setup.

Then gradually my percula also died..but my hermit crab, and snail are doing fine.

Their death totally shook me to the core..becasue I really loved them ( they even had pet names).
Also after spending 10 years in the freshwater hobby, I found it difficult to digest that my first saltwater tank couldn't even last a month properly.
I tried to do some research into why the tank crashed ..and I am a bit confused.

1) If my tank had not been cycled , and there was an ammonia spike, why weren't my fish killed off immediately?. Also they didn't die all at once, they went out in a particular order over 1 week. They didn't come up to the surface like other freshwater species suffering from high ammonia levels.

2) I did some research and saw that people do run saltwater tanks without skimmers/sumps. So where did I go wrong?

3) The temperature during December was 25 degree Celsius. During Jan it dropped to 20-22 ish. Was that an issue?

4) How did my inverts survive the ammonia spike. They are still doing fine in a separate emergency tank I had setup for them.

5) Previously I had noticed a heavy growth of diatoms in the tank..but just before the death of the fishies.they mysteriously disappeared..but no other algae took their place.

I am totally at a loss here. I don't know what happened and would appreciate it if you could help me out.

I am planning to restart my tank.and I would like to do proper research this time. I am not planning to add anything more 1 percula clownfish initially..and if it is feasible as per you guys, I might add a red knob starfish later.
Also I would love it if you could refer me to some more research material that would help me transition into the saltwater hobby.

 

[cdemoss01]

Id say proper research can help get you there. Also we are here to help! This site can get you anywhere you want. I'm guessing you know you overstocked the 15 gallon and that blue tang requires up too 80 gallons. Also if you wanna know what fish will fit in the 15 gallon click this link https://www.liveaquaria.com/category/2124/ it's what most reefers use. Don't put t anything in the 15g 4 inches and above. Start slow and add only two fish.

 

[edsbeaker]

It’s very difficult to say what may have happened with so little information. All we can do is guess.

First of all, your tank may have been cycled, but adding 4 fish in that small of a tank at the same time could have easily caused an ammonia spike causing them all to perish.

Next, you said the temperature in the tank went down to 20 degrees Celsius, and that is very cold for saltwater fish. They are usually maintained near 25 degrees Celsius and require a heater in the tank to maintain it.

Third, disease could have also been a cause. Any disease in that tank especially in combination with the low temperature and stress of the small tank could have easily spread.

I encourage you to read up on some of the information below that I am linking here for you. Saltwater is entirely different than freshwater, and you need to learn a bit more before you try this again.

https://www.reef2reef.com/threads/cycling-an-aquarium.306554/
https://www.reef2reef.com/threads/the-supreme-guide-to-setting-up-a-saltwater-reef-aquarium.138750/
https://www.reef2reef.com/threads/beginners-guide-to-acclimation-and-quarantine.304980/
https://www.reef2reef.com/threads/n...ur-tank-post-here-and-well-help.200605/unread
The link above for Liveaquaria is specifically for nano fish… all suitable for the size tank you have. Some of them are very aggressive, and some need special food, so not all will be a good match for a beginner, so research them before adding them to your tank.

https://www.liveaquaria.com/category/2124/
Good luck!!!

 

[jsmkmavity]

And no on the starfish in my opinion it will slowly starve to death.

 

[Mr. Mojo Rising]

Once you realized your error you should have returned the tang and the angelfish right away, you should not have tried to keep them. Stress easily kills saltwater fish.

To me it looks like you are making actions, and then doing the research afterwards. You have to do the research first. Put nothing into your tank unless you properly researched it, and understand how to keep it alive.

This is very different than freshwater, much more complex and requires us to do homework.

At this moment, no fish should go into your tank for 2.5 months, if there is any fish disease in the water then going fishless will let the disease die.

What kind of equipment do you have? I imagine just a small hob filter but hob filters (and canisters) have very little benefit on a saltwater tank.

 

[amoeba2006]

Id say proper research can help get you there. Also we are here to help! This site can get you anywhere you want. I'm guessing you know you overstocked the 15 gallon and that blue tang requires up too 80 gallons. Also if you wanna know what fish will fit in the 15 gallon click this link https://www.liveaquaria.com/category/2124/ it's what most reefers use. Don't put t anything in the 15g 4 inches and above. Start slow and add only two fish.

Sure. Thanks for the guidance and support

 

[amoeba2006]

It’s very difficult to say what may have happened with so little information. All we can do is guess.

First of all, your tank may have been cycled, but adding 4 fish in that small of a tank at the same time could have easily caused an ammonia spike causing them all to perish.

Next, you said the temperature in the tank went down to 20 degrees Celsius, and that is very cold for saltwater fish. They are usually maintained near 25 degrees Celsius and require a heater in the tank to maintain it.

Third, disease could have also been a cause. Any disease in that tank especially in combination with the low temperature and stress of the small tank could have easily spread.

I encourage you to read up on some of the information below that I am linking here for you. Saltwater is entirely different than freshwater, and you need to learn a bit more before you try this again.

https://www.reef2reef.com/threads/cycling-an-aquarium.306554/
https://www.reef2reef.com/threads/the-supreme-guide-to-setting-up-a-saltwater-reef-aquarium.138750/
https://www.reef2reef.com/threads/beginners-guide-to-acclimation-and-quarantine.304980/
https://www.reef2reef.com/threads/n...ur-tank-post-here-and-well-help.200605/unread
The link above for Liveaquaria is specifically for nano fish… all suitable for the size tank you have. Some of them are very aggressive, and some need special food, so not all will be a good match for a beginner, so research them before adding them to your tank.

https://www.liveaquaria.com/category/2124/
Good luck!!!

Thanks...I will be reading up everything beforehand this time. I am not going to put in anymore living creature in jeopardy.

 

[amoeba2006]

Once you realized your error you should have returned the tang and the angelfish right away, you should not have tried to keep them. Stress easily kills saltwater fish.

To me it looks like you are making actions, and then doing the research afterwards. You have to do the research first. Put nothing into your tank unless you properly researched it, and understand how to keep it alive.

This is very different than freshwater, much more complex and requires us to do homework.

At this moment, no fish should go into your tank for 2.5 months, if there is any fish disease in the water then going fishless will let the disease die.

What kind of equipment do you have? I imagine just a small hob filter but hob filters (and canisters) have very little benefit on a saltwater tank.

Well , the filter is a top filter with a flow rate of 800 litres per hour. The media basket was filled with sponges and ceramic biomedia.

What kind of filtration would you suggest? Many people on the internet suggested live rocks but they are banned in India under the Wildlife Protection Act. .

I had drained the aquarium completely, it's dry. But a bit of experience in biology tells me that bacteria , fungi are too stubborn. How do I ensure that if pathogenic microbes were present, they are dead ?

I tried returning the fish (for free ofc) , but obviously that guy won't take it back fearing it might contaminate his tank. Also there is no reefer community or forum here...where I can identify fellow saltwater aquarists.

This time I am going to just read a lot before even mixing the saltwater.

 

[amoeba2006]

And no on the starfish in my opinion it will slowly starve to death.

Ok.
What are the basic requirements that I must meet, before attempting to keep a starfish( specifically the red knobbed star)?
If I can successfully maintain my upcoming tank...I might try to setup one for them in the future..

 

[jsmkmavity]

They are beautiful and commonly sold in stores and online but better left in the ocean IMO. get an urchin and a crab instead. The urchins move in a similar way and are good cleaners.