Death To All Who Enter

[Pocaseint]

Hello,

I have a 75 gallon FOWLR tank with the following inhabitants: 1 White Spotted Puffer, 1 Yellow Tang, 2 Percula Clowns, 1 Yellow-Tail Damsel, 1 Mandarin Goby, 1 Flame Hawk Fish, and 1 Blue-tipped Angel fish. I tried adding a Gramma Basslet. Within days, the Gramma Basslet became a recluse and within a week his tail fin had been more or less destroyed. He has now disappeared completely. This is not the first time this has happened. Someone is beating the crap out of him and killing him, but I don't know who. My two primary suspects are the Tang and the Damsel, but the more important question is how do I add another fish without subjecting the new specimen to a sentence of death?

 

[Kurt_Nelson]

Just my opinion, but I think you're at - or even over - your limit to start with. Seems like whoever is doing the beating up is trying to let you know that.

 

[Pocaseint]

Okay, that's something I had not considered. My freshwater tanks carry a much heavier load, so I mistakenly (it turns out) assumed the one inch per gallon rule was a reasonable guide. I know my water quality is high, since I test that bi-weekly, the salinity is okay and so is the Ph. I'd be curious to know more about your conclusion (not that I disagree with it). Thanks.

 

[An t-iasg]

In freshwater, the one inch per gallon rule is a reasonable, but not infallible, guide. In saltwater, the guidelines expand to one inch per five gallons. Again, that's a general guideline and most "salties" I know stock way below that guideline. I'm not a salty, so I'll let Kurt elaborate.

P.S. Welcome to AA!

 

[cmor1701d]

Welcome to AA!

"The dissolved oxygen level in the water of the aquarium is the biggest limiting factor. This is more important in saltwater tanks, where the high density of the water greatly reduces the amount of available oxygen. "
Therefore the 1 fish per FIVE gallon rule for a SW tank.

Aquarium Pros goes on to say:
"Saltwater has far less dissolved oxygen than freshwater. The rule we use for saltwater is three inches of fish for every square foot of surface area. For example, a 55-Gallon aquarium (48" Long by 13" Wide) has approximately four square feet of surface area, so approximately twelve inches of fish can be kept in a 55-gallon aquarium."

That would mean your 75 could hold accommodate up to 15" - 18" of fish if conditions are kept pristine and you have enough hiding places and keep compatibility and aggressiveness in mind. Based on adult sizes I'm seeing about 34" of fish in your tank right now.


White Puffer (Arothron meleagris) Up to 1' 7" NOT SURE WHICH ONE YOU HAVE
Spotted Puffer (Canthigaster sp.) Up to 5"

Yellow Tang - (Zebrasoma flavescens) Up to 8"
Percula Clownfish (Amphiprion percula) Up to 3"
Yellowtail Damselfish (Chrysiptera parasema) Up to 3"
Flame Hawkfish (Neocirrhitus armatus) Up to 4"
Flame Angelfish (Centropyge loriculus) Up to 4"
Green Mandarin (Synchiropus splendidus) Up to 4"

I think those numbers are on the conservative side if your husbandry is good and you have great biological filtration, and a good skimmer. Even taking 1½ times those suggestions, you are overstocked right now.

 

[Pocaseint]

The Puffer (spotted) is about 5 inches in length
The two Clownfish are about 2 inches each
The Yellowtail is 3 inches
The Hawkfish is four inches
The Angelfish is four inches
The Mandarin is four inches +/-

Of course, the actual amount of water in the tank is less given the amount of live-rock. There are plenty of hiding places since I have built up two areas in each corner of the tank that provide cover and numerous passageways in and out of the rock. Given what you all have said, I am going to heed your advice. Interestingly, of all the specimens in the tank, they are all in good health and have been in the tank for several years (the Hawkfish being the longest and it has been around about 4 years). I appreciate your advice!!!!

 

[melosu58]

My suggestion would be the tang, puffer and hawk fish. Hawk fish can be quite fiesty also. Also when adding new fish I would turn out the lights and move some LR around to distract the other fish. JMO

 

[Innovator]

"Inch per whatever" rule is fallible. There is no consideration taken into effect in regards to girth, territories, behaviors, and even the rule of measurement is not consistent with respects to the hodgpodge of fish most aquarists keep. Most professionals, ime, have abandoned this rule altogether. Dissolved oxygen levels should not be of any concern with those who set up their filtration properly even by "recommended guidelines." If you wish to heavily stock your tank your filtration should be oversized. There is a reasonable mixture of fish in your system, but the only concern (based on my personal averages) I see that would have territorial aggression towards basslets would be the hawkfish, angelfish, damsel, and possibly the clownfish pair depending on if they are breeding. Personally I don't see a basslet being of any concern to the yellow tang unless that particular fish just has a parasite up its...

 

[Kurt_Nelson]

Agree that the "inch/gallon" rules aren't the best thing in the world, but at least it gives you an idea of a starting point. Seems like 5" per gallon is a pretty safe bet. If you go below that ratio (more fish) then you'd better have a good maintenance schedule and have good filtration. I've seen books that say 2" per gallon. Personally, I'm right around 3" per gallon. I can't imagine putting another fish in my tank.

My reasoning that you were overstocked was that your list of fish aren't the most docile in the world and having somewhat territorial fish in that crowded of a tank seems like things wouldn't stay healthy for long. Maybe the basslet is the straw that finally broke the camel's back, and pushed one of the fish over the edge. I can hear it now... "That's IT. I've HAD IT. I put up with the damsel, then the two clowns, then that other funky looking thing that is constantly looking for food and eating all my pods, but I'm drawing the line HERE. Buddy... you're toast."

Or maybe something like that.

My first guess was the hawkfish, and it's interesting that it's also your longest resident. Normally, when stocking a tank, it's best to start out with the more docile fish first, and add the more aggressive fish later. That way the meeker ones get a chance to establish "their" territory and feel more at ease before the big bullies move into town.

 

[Pocaseint]

The Hawkfish is my longest resident, but he/she wasn't my first. Over the years, I have had die-off and turnover. I had originally stocked the tank with the less aggressive species first, but turn-over has pretty much rednered that moot. Things are pretty stable now. Aside from the Basslet with a bullseye on it, I had a Apogon leptacanthus, but he died of some kind of illness. Interestingly, he was doing just fine, then he went pale and pass on a few days later. So the Hawkfish has been, in Darwinian terms, the fittest survivor.