Invertebrates

Chapter 1 Invertebrates

TABLE 1-1 Antimicrobial and Antifungal Agents Used in Invertebrates.a–e

Agent	Dosage	Comments
Benzalkonium chloride	0.5 mg/L long-term⁶⁶	Quaternary amine with broad disinfection properties
	10 mg/L for 10 min⁵⁶
Ceftazidime (Fortaz, Pfizer)	20 mg/kg intracardiac q72h × 3 wk⁵⁶	Spiders/cephalosporin with good activity against Gram-negative bacteria (e.g., Pseudomonas); although this regimen appears safe, efficacy has not been determined
Chloramphenicol	75 mg/kg PO, IM q12h × 6 days⁵⁹	Cephalopods
	10-50 mg/L as an immersion treatment for several days¹⁰^,⁶²^,⁶⁴ (prepare fresh solution with 100% water change q24h)	Corals/reduce lighting for treated animals if possible (slows metabolic rate and may reduce stress and improve drug tolerance); rinse animals well with fresh seawater before return to primary habitat; properly treat any effluent before discharge; florfenicol may be a better alternative (risk to humans from chloramphenicol)
Enrofloxacin (Baytril, Bayer)	5 mg/kg IM, IV²⁸^,⁵⁹	Cuttlefish and possibly other cephalopods
	5 mg/kg IV⁵⁶	Spiders
	10 mg/kg PO²⁸^,⁵⁹	Cuttlefish and possibly other cephalopods
	10-20 mg/kg IM⁶⁵	Chinese mitten crabs/PD
	10-20 mg/kg PO q24h⁵⁶	Spiders
	2.5 mg/L × 5 hr immersion q12-24h²⁸^,⁵⁹	Cuttlefish and possibly other cephalopods
Fluconazole	3 mg/kg q4d × 6 treatments⁶⁰	Horseshoe crabs
Formalin	1-1.5 ppm³⁷	Horseshoe crabs/ectocommensals
Furazolidone	50 mg/L q12h for 10 min immersion⁵⁹	Cephalopods
Iodine, Lugol’s 5% solution	5-10 drops/L of seawater; use as an immersion for 10-20 min¹⁰^,⁶⁴	Corals/antiseptic; cauterize wounds; strong oxidizing agent; some corals are sensitive, including pulse corals (Xenia sp), Anthelia spp, and star polyps (Pachyclavularia spp); remove corals at first signs of stress (polyp expulsion)
	Topically at full strength (5%) for 20-30 sec⁶⁴
Itraconazole (Sporanox, Janssen)	10 mg/kg IV¹	Horseshoe crabs/PD
Nitrofurazone	1.5 mg/L for 72 hr⁵⁹ immersion	Cephalopods/nitrofuran; carcinogenic; drug inactivated in bright light; water soluble formulations preferred
	25 mg/L q12h for 1 hr⁵⁹ immersion
Nystatin	50 mg/mL for surface “sterilization” of aquatic nematodes⁸^,⁴⁷
Oxolinic acid	10 mg/kg intrasinus⁶⁷	Kuruma shrimp/PD; quinolone; Gram-negative bacteria; decreased uptake in hard water; better uptake pH <6.9
	50 mg/kg PO⁶⁷
Oxytetracycline	10 mg/kg intrasinus⁶⁷^,⁶⁸	Tiger shrimp/PD; cooking reduced muscle levels by 30-60% and shell levels by 20%
	25 mg/kg intrasinus⁶⁷	Kuruma shrimp/PD
	25-50 mg/kg IV⁵²	Horseshoe crabs/PD
	50 mg/kg PO⁶⁷^,⁶⁸	Kuruma shrimp/PD; tiger shrimp/PD; cooking reduced muscle levels by 30-60% and shell levels by 20%
	100 mg/kg PO⁵⁷	White shrimp/PD
	200 mg/colony q4-5d × 3 treatments⁷⁰	Honeybees/for treating American and European foulbrood; withdrawal time of 6 wk; should not be used on hives where honey will be consumed by humans
	10-15 mg/L q48-72h × 3-5 treatments³³	Chocolate chip sea stars/cutaneous ulcerations; may be applicable to other echinoderms with bacterial lesions
	1 g/lb of feed⁵¹	American lobsters/gaffkemia; approved for use in food animals by the FDA
Silver sulfadiazine cream (Silvadene, Marion Merrill Dow)	Apply topically to lesions	Proceed with caution (biotest if possible) as treatments are empirical
Sulfadimethoxine	50-100 mg/kg in feed × 14 days⁵¹	Penaeid shrimp
Sulfadimethoxine/ormetoprim (Romet-30, Alpharma)	42 mg/kg intrapericardial⁴	American lobster/PD
Sulfamethoxazole/trimethoprim	Bioencapsulated in brine shrimp PO q12h¹³^,⁴⁰^,⁴⁹^,⁵⁰	White shrimp/PD; combine 20-40% trimethoprim sulfamethoxazole with a lipid emulsion (Selco, INVE Aquaculture) at a concentration of 1:5
Tetracycline	10 mg/kg PO q24h⁵⁹	Cephalopods
	10 mg/L bath³⁶^,⁶⁴	Corals/efficacy questionable in saltwater; anecdotal evidence of successful treatment for bacterial infections
Trifluralin	0.01-0.1 ppm as an immersion⁵¹	Penaeid shrimp/larval oomycetosis
Tris EDTA and neomycin (Tricide-Neo, Molecular Therapeutics)	100 mL/L for 45 min q24h × 7 days as an immersion³³	Cushion sea stars/cutaneous ulcers; may be applicable to other echinoderms
Tylosin (Tylan, Elanco)	200 mg/colony q7d × 3 treatments⁷⁰	Honeybees/antibiotic applied topically to the brood chamber for control of American foulbrood (Paenibacillus larvae); approved by the FDA; should not be used in hives where the honey will be consumed by humans
Winter savory extract (Satureja montana)	0.01% in microcrystalline sugar¹⁵	Honeybees/chalkbrood fungal disease (Ascosphaera apis); a number of plant aromatic oils have been tested, some with more promise than others, on various diseases of honeybees²⁰^,⁷⁰

^a Not to be used with invertebrates intended for human consumption unless government approved.

^b Preferable to treat a single animal of a species (biotest) to determine toxicity.

^c Tank treatment: when treating the invertebrates’ resident aquarium, disconnect activated carbon filtration to prevent drug removal. Many drugs adversely affect the nitrifying bacteria, so water quality should be monitored closely (especially ammonia and nitrite concentrations). Keep water well aerated when appropriate and monitor patient(s) closely. Perform water changes and reconnect filtration to remove residual drug following treatment. Discard carbon following drug removal.

^d Bath (immersion) treatment: remove invertebrates from resident aquarium and place in container with known volume of water and concentration of therapeutic agent. Watch closely for signs of toxicity.

^e Invertebrate species, temperature, and water quality parameters can influence the pharmacodynamics of many drugs, especially antimicrobials.

TABLE 1-2 Antiparasitic Agents Used in Invertebrates.a–e

Agent	Dosage	Comments
Acetic acid, glacial	3-5% solution for 1 hr¹²	Horseshoe crabs
Amitraz	Use as directed⁷⁰	Honeybees/acariasis; commercial packaging should be consulted prior to use
Chromic acid	0.2% immersion for several min⁹^,⁵⁸	Turbellarians/Urceolaria protozoans
Formalin	50-100 μL/L for 4 hr or 25 μL/L indefinitely⁵¹	Shrimp/protozoal ectoparasites; approved for use by the FDA in food animals
Formic acid	Use as directed⁷⁰	Honeybees/acariasis; commercial packaging should be consulted prior to use
Freshwater	1-3 min dip⁶⁴	Stony corals, some soft corals/flatworms, and other ectoparasites; buffer to pH 8.2 and use clean, dechlorinated water; do not use on small polyp corals or xenids; biotest first, if possible, especially when attempting with a new species
Fumagillin	Use as directed⁷⁰	Honeybees/nosemosis (caused by microsporidian parasites); commercial packaging should be consulted prior to use
Ivermectin	Stock solution of 1:1 (1% ivermectin and propylene glycol); dilute 1:50 with distilled water prior to topical use⁵⁶	Spiders/for the treatment of individual parasitic mites; apply carefully to mites with fine paintbrush or similar implement
Levamisole (Levasole, Schering Plough)	8 mg/L immersion for 24 hr⁶⁴	Corals/metazoan parasites; well tolerated by Acropora spp, Montipora digitata, M. capricornis, Seriatopora histrix, Stylophora pistillata
Menthol	Use as directed⁷⁰	Honeybees/acariasis; commercial packaging should be consulted prior to use
Metronidazole	50 mg/kg intracardiac × 1 treatment⁵⁶	Spiders/appears safe, but efficacy is unknown
	100 mg/L for 16 hr⁵⁹	Cephalopods/antiprotozoal
Milbemycin oxime (Interceptor, Novartis)	0.625 mg/L as an immersion²⁴^,³²^,³⁸	Stony corals (Acropora)/“red bug” (Tegastes acroporanus)
Potassium permanganate	25-30 ppm for 30-60 min⁵¹	Penaeid shrimp/external parasiticide
Povidone iodine	0.75% solution for topical treatment⁵⁶	Spiders/fungal infections; use water based solution
Thymol	Use as directed⁷⁰	Honeybees/acariasis; commercial packaging should be consulted prior to use
Triton X-100 (Sigma)	Culture turbellarian eggs in 0.25-1% solution for 4 days⁹	Turbellarian eggs/protozoan (Thraustochytrium caudivorum)

^a Not to be used with invertebrates intended for human consumption unless government approved.

^b Preferable to treat a single animal of a species (biotest) to determine toxicity.

^e Invertebrate species, temperature, and water quality parameters can influence the pharmacodynamics of many drugs.

TABLE 1-3 Chemical Restraint/Anesthetic/Analgesic Agents Used in Invertebrates.

Agent	Dosage	Comments
Benzocaine	100 mg/L²^,³⁰	Abalone/anesthesia; not sold as anesthetic in United States; available from chemical supply companies; do not use topical anesthetic products marketed for mammals; prepare stock solution in ethanol (benzocaine is poorly soluble in water); store in dark bottle at room temperature
	400 mg/L¹⁹	Leeches/this could be applied, with caution, to other aquatic annelids
	2.5-3 g/L⁵⁹	Cephalopods/euthanasia
Butorphanol	Fish, amphibian, and reptile dosages can be employed with care	Analgesia; use with caution as dosing regimens are empirical; biotest when possible
Carbon dioxide	Blow gas over animal⁹^,⁴¹	Terrestrial turbellarians/euthanasia
	3-5%³¹	Terrestrial arthropods/euthanasia; isoflurane and sevoflurane may be preferable with regard to recovery; an anesthetic chamber has been developed/described for use in the fruit fly⁷¹
Chloretone	0.1%⁹^,⁵⁵	Turbellarians/anesthesia
Clove oil (eugenol)	0.125 mL/L (approx. 125 mg/L) as an immersion²⁶	Crustaceans/stock solution: 100 mg/mL of eugenol by diluting 1 part clove oil with 9 parts 95% ethanol (eugenol is poorly soluble in water); over-the-counter preparation (pure) available at most pharmacies contains approximately 1 g eugenol per mL clove oil
Ethanol	1.5-3% solution³⁴	Cuttlefish/may not be effective for cold water cephalopods³⁰
	3% solution³⁰	Abalone
	5% solution²⁵^,³¹	Aquatic gastropods
	5% solution¹⁶^,⁴²	Oligochaetes/adequate for terrestrial earthworms such as Lumbricus terrestris
	10% solution⁶^,⁹^,⁵⁵^,⁷³	Turbellarians/anesthesia
	10% solution⁵⁹	Cephalopods/euthanasia
Ethanol/menthol (Listerine, McNeil-PPC)	10% in saline⁷⁴	Aquatic gastropods/anesthesia
Hydroxylamine hydrochloride	1% solution⁹^,⁵⁵	Turbellarians/anesthesia
Ice	Used to effect;⁹^,²² pure ice water can also be used⁹^,⁵⁵	Turbellarians/sedation; cover ice with filter paper to protect the flatworms
Isoflurane	Can be used with an anesthetic chamber	Terrestrial gastropods,²⁷ arachnids¹⁷^,²³^,⁴⁵^,⁵⁶/anesthesia; fast induction with a possible excitatory period; anesthetic depth may not be appropriate for invasive surgery;²⁷ usually applied at a 5% concentration for arachnids
Ketamine	40-90 mcg/g IM¹¹	Crayfish/induction time of less than 1 min and anesthetic duration of 10 min at low dose and 2 hr at high dose
	0.025-1 mg/kg²⁶	Australian giant crabs/fast induction (less than 30 sec) with an excitatory phase; dose dependent anesthetic duration of 8-40 min
Lidocaine	0.4-1 mg/g IM¹¹	Crayfish/induction time of less than 2 min and duration of anesthesia of 5-30 min when injected into the tail
Magnesium chloride	Intracoelomic¹⁴	Sea hares/short induction time (2-5 min) and good muscle relaxation
	6.8 g/L²⁸^,³⁰	Cephalopods/induction time of 6-12 min in cuttlefish
	30-50 g/L³⁵	Scallops/fast induction and recovery
	1:1 isotonic salt and seawater as an immersion⁷^,⁹	Marine turbellarians
	1:1 mixture of 7.5% with seawater³³^,⁴⁴	Echinoderms/concentration adjustments may be required for prolonged anesthesia
	7.5% immersion⁴⁰^,⁴⁸	Polychaetes
	10% solution prn⁵⁹	Cephalopods/euthanasia
Magnesium sulfate	Intracoelomic¹⁴	Sea hares (sea snails; Aplysia)/short induction time (2-5 min) and good muscle relaxation
	4-22 g/100 mL⁷²	Abalone/fast induction and good recovery
MS-222 (Finquel, Argent)	—	See tricaine methanesulfonate
2-phenoxyethanol	0.5-3 mL/L⁷²	Abalone/quick induction and short recovery
	1-2 mL/L³⁰	Quick induction and short recovery
Potassium chloride	1 g/kg (330 mg/mL solution) IV⁵	Lobsters/euthanasia; inject at base of second walking leg
Procaine	25 mg/kg IV⁵⁴	Crabs/very short induction time (less than 30 sec) and prolonged anesthesia (2-3 hr)
Propylene phenoxetol	1-3 mL/L of a 1% solution³⁰^,⁴⁶^,⁵³	Oysters/anesthesia; this concentration should produce anesthesia in less than 15 min; recovery time is short (under 30 min); higher doses can be used but induce a deeper level of anesthesia; can also be used for giant clams⁴⁶
	2 mL/L³⁰^,⁶⁹	Echinoderms
Sevoflurane	Can be used with an anesthetic chamber at a 5% concentration³⁰	Terrestrial arthropods/see isoflurane for details of administration
Sodium azide	100 mM³^,⁸	Nematodes (Caenorhabditis elegans)/anesthesia; can survive for 2 hr without apparent harm; sodium azide is a plant and animal cell mutagen; proper hygiene and handling is advised
Sodium bicarbonate tablets (Alka-Seltzer, Bayer)	2-4 tablets/L bath²⁹	Euthanasia; generates CO₂; use when other agents unavailable; keep aquatic invertebrate in solution >10 min after respiration stops; dosage based on piscine literature
Sodium pentobarbital	400 mg/L⁴³	Aquatic gastropods/anesthesia; very slow onset but apparently safe; controlled drug
	1 mL/L²	Abalone
Tricaine methanesulfonate (MS-222; Finquel, Argent)	Dosages and efficacy vary widely depending on species and application; consult taxon-specific literature³⁰^,³¹	Anesthesia; stock solution: 10 g/L, buffer the acidity by adding sodium bicarbonate at 10 g/L or to saturation; store stock in dark container; shelf-life of stock extended by refrigeration or freezing; stock that develops an oily film should be discarded; aerate water to prevent hypoxemia; euthanasia: keep animal in solution >20 min after respiration stops
Xylazine	16-22 mg/kg IV²⁶	Giant crabs/fast induction (3-5 min) and approx 30 min of anesthesia (dose dependent)

TABLE 1-4 Miscellaneous Agents Used in Invertebrates.

Agent	Dosage	Comments
Barium sulfate	4 mL/15 g food²¹	Tarantulas, scorpions, millipedes, hissing cockroaches/contrast radiography; inject into a strawberry and feed to millipedes; inject into crickets and/or other prey for carnivorous invertebrates
Benzocaine topical (Orabase, Colgate-Palmolive)	Topically⁶⁴	Corals and, potentially, other aquatic invertebrates/used as a water-resistant paste; chemotherapeutics can be combined for topical therapy
Carbon, activated	75 g/40 L tank water⁵¹	Removal of medications and other organics from water; usually added to filter system; discard after 2 wk; 75 g 250 cc dry volume
Chlorine/chloramine neutralizer	Use as directed	See sodium thiosulfate
Diatrizoate meglumine and diatrizoate sodium (Hypaque-76, Amersham Health)	4 mL/15 g food²¹	Tarantulas, scorpions, millipedes, hissing cockroaches/contrast radiography; combine with/inject into the food item and feed 1-3 hr prior to radiography
Hydrogen peroxide (3%)	0.25 mL/L water⁵⁰	Acute environmental hypoxia; dose from the piscine literature
Iohexol	12 mL/kg IV	Horseshoe crabs/contrast radiography
	15 mL PO⁶¹
Methylmethacrylate	Apply topically as needed¹⁸^,⁵⁶	Arthropods (spiders, scorpions, insects)/repair fractured exoskeleton; there are numerous references for the application of surgical adhesives, so consult the appropriate taxon-based literature
Mineral oil	1 mL/kg PO	Insects/laxative¹⁸
Nitrifying bacteria	Use as directed for commercial products	Seed or improve development of biological filtration to detoxify ammonia, nitrite, and nitrate; numerous commercial preparations; do not expose products to extreme temperatures; use before expiration date
	Add material (e.g., floss, gravel) from a tank with an active biological filter and healthy fish to new tank⁵⁰	Must evaluate risk of disease transmission with this technique
Oxygen (100%)	Fill plastic bag with O₂ containing 1/3 vol of water²⁹	Acute environmental hypoxia common with transportation; close bag tightly with rubberband; keep animals in bag until normal swimming and respiratory behavior
Sodium thiosulfate	Use as directed for chlorine/chloramine neutralizers	Active ingredient in numerous chlorine/chloramine neutralizers; chlorine and chloramine are common additions to municipal water supplies and are toxic to many aquatic invertebrates; ammonia released by detoxification of chloramine is removed by functioning biological filter (see nitrifying bacteria) or chemical means (see zeolite)
	10 mg/L tank water³⁹
	10 g neutralizes chlorine (up to 2 mg/L) in 1000 L water³⁹
	100 mg/L tank water⁶³	Chlorine exposure
Zeolite (i.e., clinoptilite) (Ammonex, Argent)	Use as directed	Ion-exchange resin that exchanges ammonia for sodium ions; clinoptilite is an active form of zeolite; used to reduce or prevent ammonia toxicity
	20 g/L tank water⁵⁰