Disinfection of aquatic vegetation.
Just like fish, newly acquired plants must be treated as they can carry pathogens of infectious plant diseases. Along with plants, you can introduce snails, fish eggs, and disease pathogens into your aquarium. Many plants you purchase may be imported or simply grown in conditions vastly different from your aquarium. Be prepared that some specimens of your newly acquired plants will require an adaptation or even rehabilitation period, and might completely shed their leaves and grow new ones. If the plant is alive, roots will grow.
The easiest plants to adapt are those grown in similar water and sold shortly after being removed from their original aquarium. However, this does not mean you shouldn’t buy imported plants from pet stores; you just need to pay a little more attention to some of them. When choosing plants, you must understand that many of them grow in nature at depths of no more than 30 cm or even in damp soil periodically flooded with water. Accordingly, you won’t be able to grow everything in a deep aquarium.
Plants, unless they are to be discarded, should be disinfected. Before placing purchased plants into your aquarium, they must be treated to prevent the introduction of algae, plant pests like water aphids, snails and their eggs, fish disease pathogens, and parasites. Never neglect this rule! Do not acquire any aquarium plants from tanks containing algae or plants showing signs of algae. Thoroughly inspect plants before placing them in the aquarium. Check for algae infestation and discard if necessary. All newly acquired plants should be treated in a separate container to eliminate snails; you can use Sera Snail ex, but increase the dose several times.
Plants should be undamaged, meaning free of holes, yellow or brown spots, and slimy patches. Before planting, each plant must be cleaned of attached filamentous algae, snail eggs, and decayed areas; diseased and rotting parts should be removed, and roots cleaned of dirt. If you notice any leaves or other parts of the plant starting to rot, remove them as quickly as possible using a scalpel and tweezers. Roots can be trimmed slightly to prevent them from bending during planting and to stimulate rapid growth. Plants with few thin roots should either be left untouched or trimmed very moderately.
Recipes for prophylactic plant solutions.
• Keep plants for at least 15 days, with the first 12 days at 24-26°C, followed by 3 days at 32-34°C.
• Bicillin-5 solution at a rate of 1,500,000 IU per 10 liters, exposure for 30 minutes daily. Repeat the procedure for 5 nights. Pour out the old solution before applying repeated doses.
• Buprofezin 0.01% for 120 minutes.
• Imidacloprid 18.3% v/v 0.005% for 45-60 minutes.
• Trichlorfon (trichlorphon, chlorofos) 0.8% for 120 minutes.
• In a 0.1% pink potassium permanganate solution. Exposure for 10-15 min.
• Potassium permanganate solution, followed by soaking in water with potassium nitrate, potassium monophosphate, and magnesium sulfate as fertilizer for 2-4 hours.
• 20% aqueous ammonia solution at a 1:500 ratio, exposure for 1 minute.
• Aqueous solution of 3% hydrogen peroxide, exposure for 5 minutes. Rinsing with hydrogen peroxide (1 teaspoon per 1 liter of water).
• A bath (5-10 minutes) with an alum solution (1 teaspoon per 1 liter of water) is also recommended.
• Methylene blue 0.5 g/l, exposure for 10 minutes.
• Place them in a bleach solution for 3-5 minutes (1 part bleach to 30-40 parts water) and rinse thoroughly from chlorine in clean room-temperature water.
After such treatment, the plant should be rinsed carefully and can be planted in the aquarium.
Treatment of aquatic plants against fish disease pathogens.
Aquatic vegetation is often a mechanical vector for pathogens of many infectious diseases in aquarium fish. For a number of diseases whose treatment methods have not yet been developed, all aquatic vegetation is destroyed. Often, aquariums contain aquatic plants that are rarer and more valuable by species composition than the fish themselves. Naturally, amateur aquarists do not always destroy these plants even in the case of such dangerous diseases as mycobacteriosis, ulcer disease, lepidortheosis, and ichthyosporidiosis.
At best, plants are washed with water and placed in low-concentration solutions of medications (potassium permanganate, table salt, etc.). However, such solutions do not rid plants of pathogens such as monogenean flukes (Dactylogyrus, Gyrodactylus) or most parasitic protozoa. Increasing the concentration of disinfecting solutions leads to plant death. If the aquarium, substrate, fish-farming equipment, and fishing gear are thoroughly disinfected and the fish stock is replaced with healthy ones, but plants treated in the specified manner are placed back into the aquarium, the fish will fall ill again after some time.
However, there is an effective and plant-safe treatment method against most fish disease pathogens using the antibiotic bicillin-5. This method involves 
prophylactic treatment of aquatic vegetation in the following cases:
• disinfection of vegetation from aquariums affected by mycobacteriosis, ulcer disease, fin rot, ichthyosporidiosis, dermatomycosis, ichthyophthiriosis, chilodonellosis, trichodiniosis, costiosis, oodiniosis, octomitiasis, dactylogyrosis, and gyrodactylosis of fish;
• disinfection of vegetation harvested from rivers, ponds, lakes, and reservoirs for acclimatization and breeding in aquariums with exotic fish;
• disinfection of vegetation taken from aquariums with an unknown epizootic status.
Bicillin-5, when added to aquarium water, inhibits certain plant species. You can also use a penicillin solution (50 mg per 10 L) for 2-3 days.
Experiments on disinfecting plants taken from aquariums affected by sporozoan fish diseases have not yielded positive results. As known, fish sick with pleistophorosis, glugeosis, and nodular disease release a large number of spores into the external environment (water), inside which the disease pathogen remains in a resting stage until a certain moment. Fish swallow these spores with food and water. In their intestines, digestive enzymes dissolve the spore coat, and the pathogen penetrates via the blood into its target organs and tissues, causing the disease. The protective coat of the spore while in water protects the pathogen from the toxic effects of the bicillin-5 disinfecting solution. Thus, the proposed method does not rid aquatic vegetation of pleistophorosis, glugeosis, and nodular disease pathogens. Therefore, the plants must be destroyed.
Aquatic vegetation, previously thoroughly washed with water (20-25°C), is placed in a small 10-liter container with well-settled water. For six days, a stock solution of bicillin-5 is added to the container with plants at a rate of 15,000 IU per 1 L of water. Only freshly prepared antibiotic stock solution should be used daily, prepared in a clean 200-250 ml glass by adding the required amount of bicillin-5 for the container volume to water at 28°C, mixing quickly, and immediately adding it to the plant container. Afterwards, the disinfecting solution with plants is gently stirred to ensure that every single part of the plants is completely submerged in the solution. Before the second and subsequent additions of the antibiotic stock solution, the disinfecting solution in which the plants were kept during the previous 24 hours is replaced with fresh settled water.
For six days, the temperature of the disinfecting solution in the plant container is maintained at 24-26°C. During the first 2 hours after each addition of the bicillin-5 stock solution, the plant container is darkened. It is best to add the antibiotic solution at night. At other times, it is kept under normal lighting, avoiding direct sunlight. On the sixth day, 2 hours after adding the bicillin-5 stock solution, the plants are removed from the container, rinsed with water (20-25°C), and placed into the fish aquarium. Aquatic plants treated using the method described above will produce their first shoots within 3-15 days under normal maintenance conditions. This method can be used to treat most species of aquarium aquatic vegetation.
Amateur aquarists should remember that for a number of fish diseases, treating aquatic vegetation with any medications, including bicillin-5, is not strictly necessary because certain fish disease pathogens die if they fail to find a fish host within several days. These include pathogens of ichthyophthiriosis, trichodiniosis, chilodonellosis, costiosis, oodiniosis, octomitiasis, cryptobiosis, dactylogyrosis, and gyrodactylosis. In this case, it is sufficient to remove the fish from the aquarium for 15 days, leaving the plants, substrate, and decorations inside. Water temperature is maintained at 24-26°C for 12 days and raised to 32-33°C for the following three days.
Parasites not covered by a cyst die in the first few days. Encysted parasites emerge into the water within 3-12 days at an optimal temperature for them, and die within the next three days if they fail to find a fish host. Moreover, a water temperature of 32-33°C is lethal to them while harmless to most aquatic vegetation. This recommendation for disinfecting aquatic vegetation applies when fish have a mixed infestation. When fish are affected by a single listed disease pathogen, the duration of fish removal from the aquarium depends on the biological characteristics of the parasite, specifically its ability to form resting stages.
Quarantine of purchased plants.
Shrimprover aquarists have repeatedly faced mass shrimp mortality after introducing new, store-bought aquarium plants into their tanks, especially from pet shops. Not everyone knows that to prevent the transmission of parasites or harmful insects with plants, suppliers treat them with insecticides before shipping that are dangerous to aquarium shrimp and crayfish. The chemicals used by plant suppliers are safe for the absolute majority of fish.
Phytosanitary certification laws—meaning the treatment of exported plants—prescribe different disinfection methods (agents) in each country, but they are mandatory everywhere. The duration and water parameters required before placing plants into an invertebrate tank depend on the chemical used to treat them. This information can be especially useful if you manage to find out exactly what the purchased plants were treated with.
For example, it is known that Asian and European suppliers use the following insecticides to treat exported plants: • buprofezin 0.01% for 120 minutes; – imidacloprid 18.3% v/v 0.005% for 45-60 minutes; • trichlorfon (trichlorphon, chlorofos) 0.8% for 120 minutes; • potassium permanganate solution followed by soaking in water with potassium nitrate, potassium monophosphate, and magnesium sulfate as fertilizer for 2-4 hours. Aquarium shrimp acquire a pink or purple tint after such plants are placed in the aquarium without quarantine.
How to get rid of chemical residues on plants before planting them in an active aquarium populated with invertebrates? Depending on the disinfectant, methods will vary. Unfortunately, these methods will only partially eliminate toxic substances from the plants. To completely wash insecticides off aquarium plants, a very long quarantine period is necessary.
For instance, buprofezin, like other acaricides, degrades in water at pH 5.0 and 20°C in 16 to 50 days. It is also stable in alkaline water (high pH). Although the concentration of buprofezin in the treatment solution is low, it is fatal to aquarium shrimp. Furthermore, buprofezin inhibits chitin synthesis, which is the primary building material for crustacean shells. Quarantining plants treated with buprofezin must be carried out for at least 48 hours under light, with frequent water changes (ideally in a running water tank).
Imidacloprid is non-toxic to fish, more toxic to aquarium crayfish, and highly toxic to snails and shrimp. Additionally, it has a side effect of lowering CO2 levels under light. Imidacloprid breaks down by half in water with a neutral pH; at low pH values, the half-life is 70-100 days. In alkaline water, unfortunately, it also lingers for a long time. The maximum an aquarist can do is keep plants treated with this substance in high-pH water for at least 48 hours (the longer, the better) with frequent water changes.
Trichlorfon (chlorofos) is a very aggressive organophosphorus pesticide. It kills not only shrimp but also daphnia. In acidic water (pH 5.0) at 20°C, it can persist for up to 526 days! However, in alkaline water (pH 8.5), 99% of it breaks down within 2 hours. Yet, its breakdown product—dichlorvos—is also an insecticide toxic to invertebrates.
On one hand, this sounds quite grim, especially considering there are other insecticides used during plant sales that the end buyer is not informed about. On the other hand, a very important conclusion arises: never neglect quarantining acquired plants before placing them into an invertebrate aquarium! Quarantining newly acquired flora is mandatory, and the longer, the better—at least two days, in alkaline water, under light, with frequent rinsing under running water and water changes in the quarantine tank.
