An Article Discussing The Fifteen Most Common Problems In The Tropical Marine Tank.
In the main, marine fishkeeping is not difficult. But common problems do occur from time to time and although these tend to be of an elementary nature, a significant number of aquarists find difficulty in resolving them unless they have definite and reliable guidelines to refer to. What follows is an outline of the fifteen most common problems I have encountered during my years in the marine fishkeeping hobby and a guide as to how to resolve them.
1) The Tank Is Too Small
Unlike freshwater, saltwater tends to be unstable in small quantities. The pH may drop suddenly, even overnight, to dangerously low levels; ammonia and nitrite surges are more likely, and nitrate build-ups can be rapid. All this generally leads to a disastrous beginning to the hobby. Most experienced hobbyists agree that a tank of over 20 imperial gallons is a good starting point for newcomers. That means a tank no smaller than 36" x 15" x 12". Remember the old maxim "large is good but bigger is better!".
2) The Aquarium Is Insufficiently Matured To Support Livestock
Before livestock can be introduced, the biological filter(s) have to contain sufficient 'friendly' bacteria to convert ammonia to nitrites and nitrites to nitrates. To confirm this properly it is wise to be able to measure the maturation process as it happens. By using a proprietary liquid maturation fluid, together with an ammonia and nitrite test kit it is possible to graph how both substances peak and then drop to zero as bacteria arrive and multiply. The procedure can take up to 28 days of nail-biting patience but it is generally the most satisfactory and successful method of maturation.
Live bacterial cultures can also be purchased, being usually stored in a refrigerator to maintain the high quantities of bacteria. This method can also prove effective. However, maturation with the use of Damsels or 'seeded' gravel presents many problems and is not to be relied upon.
3) Stocking Too Fast
Once a tank is matured, the temptation is to rush out and buy a whole selection of fish in a short period of time. The result? Usually the loss of all fish within 24 hours due to ammonia/nitrite poisoning, or, at the very least, an outbreak of a potentially fatal disease. To avoid this grim scenario, stock very slowly. One fish every three weeks is a sensible rate and gives the filter bacteria a chance to adjust to each extra load without stressing the new or existing livestock.
4) Overstocking
A close cousin of the preceding problem, overstocking is a killer, make no mistake. Again, it is related to the amount of bacteria present within the filtration system. It should be borne in mind that any filter has a maximum capacity, which, once reached, cannot be exceeded. Once it is exceeded, the tank is overstocked and this can lead to unexplained deaths and recurrent diseases.
Luckily, there is a traditional stocking ratio that works well in nearly all instances. They are, for the fish-only tank, 1" of fish for every 4 gallons (nett) during the first six months in the life of a new aquarium, increasing to 1" to every 2 gallons (nett) over the next six months. If the aquarium contains invertebrates, then fish stocking levels are drastically reduced to 1" of fish for every 6 gallons (nett) maximum over a period of one year. Most invertebrates produce very little in the way of waste and maximum stocking levels are usually governed by space restrictions only.
5) No Viable Stocking Plan
The value of a good stocking plan is often understated with many aquarists buying on impulse as the occasion arises. 'A happy tank is a healthy tank' is certainly a true saying in this instance, for if little regard is given to the compatibility of fish or fish/invertebrates a tank can quickly become a stressful environment full of disease and injuries.
For the newcomer, the period in which the aquarium is maturing need not be wasted and can relieve the itch to get something moving into the aquarium - make a stocking plan. This involves deciding which fish are desirable and compatible, and in which order they are to be introduced. The slightly more delicate species need to be established first, with the more robust ones being left until last. Maximum stocking levels can be worked out accurately with a good margin for growth being left. In this way, all the problems associated with stocking and incompatibility can be avoided from the outset.
6) Overfeeding
Every time fish are fed, two things happen.
a) The fish are sustained and
b) the filter bacteria are fed by the waste products (in fact, there are waste products that bacteria will not deal with, but more of that later).
Fish from the coral reefs will thrive on surprisingly little food as long as it is regular and varied. If possible, feed twice a day, once with a frozen food and once with a good quality marine flake. All the food should be eaten within the space of a few minutes with any uneaten particles being removed as these will pollute the water and overload the filtration system. In a very short space of time, the newcomer will be able to accurately assess the amount of food required. If in doubt, reduce amounts; the fish will not suffer.
7) Insufficient Filtration
Marine fish cannot hope to be kept properly and reliably without an effective filtration system. This may take the form of undergravels, trickle filters or biological canister; or a combination.
Other essential forms of filtration should not, however, be neglected. Protein skimmers and carbon must form the basis of any effective system as they remove waste substances that the biological filter cannot.
8) The Aquarium Is Wrongly Positioned
By placing the tank in bright, natural light unwanted algae may form and the sun may send temperatures soaring to unsafe levels. Equally, tanks positioned in dark inhospitable spots will most likely be neglected and unappreciated. Banging doors or loud music will stress aquarium inhabitants greatly, leading to disease or even death. Bear these simple, but important factors in mind before any final decision is made.
9) Wrong Lighting
Obviously the lighting should suit the type of livestock kept. Light-loving corals require high intensity lighting of the correct spectrum, whereas some fish like groupers, cardinals and squirrelfish appreciate subdued illumination. There are many tubes and spotlights available to the aquarist and it is important to investigate the properties of several before an informed decision can be made.
10) Wrong Equipment
Most equipment on the market has been thoroughly researched to suit a particular application, and manufacturer's instructions should be followed as closely as possible. Therefore, do not expect a filter designed for a 30 gallon tank to be as effective in a 50 gallon aquarium without proper back-up.
11) Nitrates Too High
Nitrates are the least toxic of the ammonia, nitrite, nitrate triangle. However, they can cause fish to become more susceptible to disease, lose their appetite and generally put extra stress upon them. Invertebrates are particularly sensitive and levels should be kept in single figures if at all possible. Nitrates can be kept low by a number of methods:- nitrate-free water changes of the correct quantity and frequency, keeping the amount of fish stocks low, not overfeeding, supplying anaerobic areas where the nitrates can be converted into harmless free nitrogen gas.
12) Too Much Nuisance Algae
Nuisance algae usually comes in the form of smothering hair or slime algae. It can not only make the tank look awful but it can harm sessile invertebrates by overwhelming them. The causes can be many and varied but mostly traceable to poor water conditions. I have A long self-help article in the archive section of my web site that supplies every answer I Can think of!
13) How Can I Obtain Reliable Information And How Much Should I Know?
a) Through knowledgeable dealers, books, magazines and Internet resources. Do not expect to have a successful tank by the 'one bridge at a time' approach.
b) Find out all you can before any purchases are made. It's easy to change your mind on paper but not so easy once things are set up.
14) Are Major Problems Easy To Rectify?
In the main, no. Good planning is the secret of success, do not rely on being able to easily cure mistakes after the event.
15) If I Have A Specific Problem, Who Can I Turn To For Advice?
Many magazines have a problem page facility as do many web sites, discussion forums and newsgroups. A knowledgeable dealer is worth their weight in gold and should be seen as a great ally.
© Nick Dakin. May not be reproduced in part, or whole, without permission.
