Venom derived molecules are increasingly being investigated as potential therapeutic agents, due to their unique biological features. While several marine bioactive compounds have been explored in animal models, no studies to date have evaluated venom proteins fractions from Chironex fleckeri for immune disease, specifically rheumatoid arthritis (RA). These fractions were tested both as monotherapy and in combination with methotrexate (MTX), the current first-line disease-modifying antirheumatic drug (DMARD), to assess potential additive or synergistic effects. Seventy-two DBA/J1 Mice were randomized into nine experimental groups: (1) Positive Control (C), (2) Arthritis Control (A), (3) Arthritis + Methotrexate (AM), (4) Arthritis + Fraction 1 (10 mg/kg) (AP1-10), (5) Arthritis + Fraction 1 (20 mg/kg) (AP1-20), (6) Arthritis + Fraction 1 (10 mg/kg) combined with MTX (AMP1-10), (7) Arthritis + Fraction 1 (20 mg/kg) combined with MTX (AMP1-20), (8) Arthritis + Fraction 5 (20 mg/kg) (AP5-20), and (9) Arthritis + Fraction 5 (20 mg/kg) combined with MTX (AMP5-20). Parameters used to determine an anti-inflammatory effect included paw oedema, paw thickness and more. Results suggest that Chironex fleckeri’s fraction 5 elicited an anti-inflammatory response in a murine collagen induced arthritis model greater than methotrexate alone and in combination. Other parameters also supported this as clinical score decreased as well as paw oedema and paw thickness. Due to the nature of the study of the fractions being investigated for the first time, significant results found in this study should be further investigated. Nonetheless, all parameters having significant results suggest that Chironex fleckeri’s fractionated venom poses potential anti-inflammatory components which can be further investigated to be used as a potential therapeutic in inflammatory diseases.