Complete Amateur, curious compared to Tropical?

[underthesea1]

I've posted a thread in the freshwater section, but as it has been on my mind, I thought I would ask here.

I currently have a tropical tank, but marine tanks are what I really love, I just have zero experience with them and have no idea on their maintenance compared to a tropical tank.

I wouldn't want anything that requires lots of maintenance, so they may not be for me, but I do wonder, if I bought an all in one tank (with a filter, skimmer all integrated), what do you have to do to keep the tank running compared to a tropical tank?

Basically, I am a total newbie, and curious and would like to know if having a small marine set up would be something I could manage, or whether I should stay well away!

Thank you x

 

[Colin_T]

Just treat it like a freshwater tank. Do a water change every couple of weeks. Monitor ammonia, nitrite, nitrate, pH and salinity (salt level). If you grow macro algae in the tank they help keep the water cleaner for longer (like plants do in freshwater). A protein skimmer can help keep the water cleaner for longer too but isn't essential.

If you want live corals they require good light and water movement but a fish only or fish and live rock tank is no different to freshwater, apart from the salt.

 

[underthesea1]

Thanks Colin, I think IF I were to go into it, I'd like a bit of coral, but I suppose there is no need to everything at once, could do that once I felt more confident.

I rarely check my tropical tanks ammonia, nitrate levels etc, probably should do it more often!

 

[jaylach]

I've had both salt and fresh water tanks but have never done coral. Still, in either case, the tank size is important as to how maintenance is needed.

Personally I consider 30 gallons the bare minimum for salt water even though many have had successful 5/10 gallon salt. Even though some would disagree I also consider under gravel filtration essential with salt.

With smaller tanks fresh water is probably easier to keep but larger tanks, 100 gallon plus, salt is probably easier. In both cases we are trying to mimic nature which we will never actually achieve. Still, in a smaller tank it is easier to do with fresh water than salt. Seems off but I have found it true that in larger tanks salt is easier.

Fresh water is also easier to treat for illness. Don't know why this is but you can use several antibiotics in a fresh water tank. You can't do this in salt as the antibiotics will kill the entire tank by killing the good bacteria. In salt you pretty much use poisons to cure fish such as copper. It becomes a serious issue of adding enough poison to kill the bad without killing the fish.

 

[Colin_T]

Personally I consider 30 gallons the bare minimum for salt water even though many have had successful 5/10 gallon salt. Even though some would disagree I also consider under gravel filtration essential with salt.

The problem with undergravel filters in marine tanks is if you have big rocks in the tank. A lot of people want rocks for the fish to hide among and the rocks stop water flowing through the undergravel filter. This means less filtration area and possible dead (anaerobic) pockets under the rocks. Undergravel filters need to be gravel cleaned regularly to keep them clean (just like you clean a power filter) and you can't gravel clean the substrate if it's covered in big rocks. Undergravel filters can be used in marine tanks but not if you plan on having a lot of rocks in the tank. Having an external filter of some sort (canister, trickle, sump, refugium) makes it easier to clean the filter if you have lots of rock in the tank.

With smaller tanks fresh water is probably easier to keep but larger tanks, 100 gallon plus, salt is probably easier. In both cases we are trying to mimic nature which we will never actually achieve. Still, in a smaller tank it is easier to do with fresh water than salt. Seems off but I have found it true that in larger tanks salt is easier.

The bigger the tank the more stable the water quality and the easier it is to keep fish. This is true for fresh, brackish or salt water. Marine tanks have a high pH (8.5) and any ammonia produced in water with this pH is extremely toxic. So the more water there is to dilute any ammonia, the better. However, once the filter has established (by cycling the tank & filter in the same way you do for freshwater) you shouldn't have any issues with ammonia. But larger volumes of water are better for water stability (ammonia, nitrite, nitrate, and everything else that builds up in them). Bigger tanks also give you more options to the fish you can keep.

Fresh water is also easier to treat for illness. Don't know why this is but you can use several antibiotics in a fresh water tank. You can't do this in salt as the antibiotics will kill the entire tank by killing the good bacteria. In salt you pretty much use poisons to cure fish such as copper. It becomes a serious issue of adding enough poison to kill the bad without killing the fish.

Marine fish get treated in the same way as freshwater fish. If antibiotics kill the filter bacteria in a marine tank, they will also kill it in a freshwater tank.

Copper is an old school treatment for marine tanks and was used primarily for whitespot and various other external protozoan parasites. Most of these can be treated with Malachite Green, formaldehyde or other chemicals. Copper doesn't get used much now because a lot of people who have marine tanks have invertebrates in them and copper kills invertebrates.

Having said that, marine fish are not as commonly infected with diseases (compared to freshwater fishes) when you buy them from a shop. This means you are much less likely to need to treat them. And with all fish it's a good idea to quarantine them for a month before adding them to an established display tank to reduce or prevent the introduction of diseases into the main display tank.

 

[jaylach]

The problem with undergravel filters in marine tanks is if you have big rocks in the tank. A lot of people want rocks for the fish to hide among and the rocks stop water flowing through the undergravel filter. This means less filtration area and possible dead (anaerobic) pockets under the rocks. Undergravel filters need to be gravel cleaned regularly to keep them clean (just like you clean a power filter) and you can't gravel clean the substrate if it's covered in big rocks. Undergravel filters can be used in marine tanks but not if you plan on having a lot of rocks in the tank. Having an external filter of some sort (canister, trickle, sump, refugium) makes it easier to clean the filter if you have lots of rock in the tank.



The bigger the tank the more stable the water quality and the easier it is to keep fish. This is true for fresh, brackish or salt water. Marine tanks have a high pH (8.5) and any ammonia produced in water with this pH is extremely toxic. So the more water there is to dilute any ammonia, the better. However, once the filter has established (by cycling the tank & filter in the same way you do for freshwater) you shouldn't have any issues with ammonia. But larger volumes of water are better for water stability (ammonia, nitrite, nitrate, and everything else that builds up in them). Bigger tanks also give you more options to the fish you can keep.



Marine fish get treated in the same way as freshwater fish. If antibiotics kill the filter bacteria in a marine tank, they will also kill it in a freshwater tank.

Copper is an old school treatment for marine tanks and was used primarily for whitespot and various other external protozoan parasites. Most of these can be treated with Malachite Green, formaldehyde or other chemicals. Copper doesn't get used much now because a lot of people who have marine tanks have invertebrates in them and copper kills invertebrates.

Having said that, marine fish are not as commonly infected with diseases (compared to freshwater fishes) when you buy them from a shop. This means you are much less likely to need to treat them. And with all fish it's a good idea to quarantine them for a month before adding them to an established display tank to reduce or prevent the introduction of diseases into the main display tank.

Point taken as to big rocks possibly blocking water flow through under gravel filtration but this is where proper design comes in. I would never use large surface covering rocks with under gravel. It would be like blocking half the input of any other type of filter. To me it would just be foolish to block flow. Still, with proper design, you can have large rocks with under gravel filtration. Just use spacers between the filter plates and rock to raise a quarter inch above the substrate. Yes, the flow through the substrate will be less than in open areas but there will still be flow. Even though the flow through the substrate may be less under large rocks even with spacing there will still be flow which removes the threat of dead (anaerobic) pockets under the rocks.

Also one needs to know how to setup under gravel filtration. Most people that would even consider using would thing that small gravel would be best but this is far from true. What I call large river pebbles are what I consider the best as they allow the best flow while still being a filter.

Sigh, I still get your points as I would not be using river pebbles in a salt tank. It has been MANY years since I've done salt but I always used ... Had to look and while it just doesn't sound right I used something like Aragonite. Still large enough for under gravel filtration but would have a much lesser freedom of water flow which, I agree, could be an issue with large obstructions.

Of course under gravel filtration has some issues but explain to me any filtration method that does not have issues. None are perfect but I truly believe that under gravel is the closest to nature if looking for a river based fish population. Still that does not answer as to salt as salt is going to be ocean, not a river. Still I think under gravel is best as even given reasonably obstructions there is no other filter method that has even close to the filter media as the entire substrate is the media.

Even if using small gauge gravel large rock obstructions can be solved simply bu using some air line under the large rocks that input from an open area. While likely less than the open substrate the air lines will still cause flow through the substrate under the large rocks. In this case I don't mean pushing air.The lines just allow water flow under the big rocks.

I know that most will disagree but I just can't see any filtration that is as close to nature than under gravel.

 

[MaloK]

One important point to keep in mind for Live Rock, is to have at least the weight recommended for the tank size.

That will help tremendously dealing with nitrate in a natural way.

A 30 gallons (36'x12'x16') will need between 22 an 50 lbs of live rock to function properly.

 

[TwoTankAmin]

It is not quite accurate to say the bacteria in sw and fw are the same. At best they are similar. In an established freshwater tank the ammonia oxidizers are not one strain of bacteria, over time different strains colonize. In sw the variety is way less diverse. So the odds are fairly decent that some of those in fw may survive a medication while in sw they are killed.

I can post a paper which measured the AOA, AOB and NOB in FW and SW aquariums. Here is what they found.

McKnight, M.M. and Neufeld, J.D., 2021. Microbial community analysis of biofilters reveals a dominance of either comammox Nitrospira or archaea as ammonia oxidizers in freshwater aquaria. BioRxiv, pp.2021-11.

Abstract
Nitrification by aquarium biofilters transforms toxic ammonia waste (NH3/NH4+) to less toxic nitrate (NO3-) via nitrite (NO2-). Ammonia oxidation is mediated by ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), and the recently discovered complete ammonia oxidizing (comammox) Nitrospira. Prior to the discovery of comammox Nitrospira, previous research revealed that AOA dominate among ammonia oxidizers in freshwater biofilters. Here, we characterized the composition of aquarium filter microbial communities and quantified the abundance of all three known groups of ammonia oxidizers. Aquarium biofilter and water samples were collected from representative freshwater and saltwater systems in Southwestern Ontario, Canada. Using extracted DNA, we performed
16S rRNA gene sequencing and quantitative PCR (qPCR) to assess community composition and quantify the abundance of amoA genes, respectively. Our results show that aquarium biofilter microbial communities were consistently represented by putative heterotrophs of the Proteobacteria and Bacteroides phyla, with distinct profiles associated with fresh versus saltwater biofilters. Among
nitrifiers, comammox Nitrospira amoA genes were detected in all 38 freshwater aquarium biofilter samples and were the most abundant ammonia oxidizer in 30 of these samples, with the remaining biofilters dominated by AOA, based on amoA gene abundances. In saltwater biofilters, AOA or AOB were differentially abundant, with no comammox Nitrospira detected. These results demonstrate that comammox Nitrospira play an important role in biofilter nitrification that has been previously overlooked and such microcosms are useful for exploring the ecology of nitrification for future research.


Basically, the recently discovered Nitrospira strains that can process ammonia to nitrate directly turn out to be the major ammonia oxidizers in FW tanks. I had been thought that AOA (ammonia oxidizing archaea) were the dominant ammonia oxidizers in FW aquariums until the new Nitrospira strains were discovered. But there are still AOB and NOB in tanks at work as well.

The more the science discovers in this respect, the more we understand about what is keeping our fish safe from ammonia etc. in our tanks.

When I got ino the hobby the 3rd of Dr, Hovanec's papers on the bacteria in our tanks was published. These basically showed the bacteria in waste treatment were not the ones in tanks, Then he identified Nitrospira as being the dominant nitrite converters and varieties of Nitrosomonas were the dominant ammmonia oxidisers.

Then the ammonia oxidizing archaea were discovered and what we new changed. They were initially found on the underside of a rock in a sw tank in a public aaquarium, It turns out they are everywhere, not just in SW.

Almost a decade later it was discovered that some strains of Nitrospira were able to process ammonia straight to nitrate (these are called comammox Nitrospira). And, again what we knew changed.

And then the above paper concluded that the not only were there differences in the strains of ammonia oxidizers but that the Nitrospira in fw and sw were different strains. In fw the comammox Nitrospira dominated but were not in sw. There they only found the Nitrospira which only converts nitrite to nitrate. And, again we knew has changed.

There is one other big difference between nitrite levels in fw and sw which has been know for some time. Chloride in the water blocks nitrite from entering fish. This is why nitrite is not usually an issue for fish in sw.

I have been looking at research trying discover if their is any difference in the composition and nature of the nitrifying biofilms in fw vs. sw. I have had no luck so far. What I do know is that in fw, the biofilm can protect the inhabitants against antibiotics. "Most nitrifiers, the bacteria responsible for nitrification, are Gram Negative." So this would suggest that antibiotics which work against gram negative bacter would do a lot of damage to out bio-filtration. So might some of the full spectrum antibiotics. But, the science has shown that the biofilms actually protect the bacteria from many of these. I know this is the case for fw.

Since I have never had brackish or sw tanks, I have not focused on them bacteria in them. It is hard enough trying to learn about and understand fw. I know there are similarities and difference and some of the general explanations but that is all.

edited for a number of egregious typos and incomplete words. I need an editor.